View source for United States Secretary of Defense

{{Short description|Head of the US Department of Defense}}
{{pp|small=yes}}
{{Use American English|date=July 2019}}
{{Use mdy dates|date=November 2022}}
{{Infobox official post
| post = United States Secretary
| body = Defense
| native_name = 
| insignia = US Department of Defense seal.svg
| insigniasize = 
| insigniacaption = Seal of the department<ref name="DoD50:177">[[#DoD50|Trask & Goldberg]]: p. 177.</ref>
| flag = Flag of the United States Secretary of Defense.svg
| flagsize = 
| flagborder = yes
| flagcaption = [[Flags of the United States Armed Forces#Personal flags|Flag of the secretary]]<ref>{{Cite web |title=Positional Colors for the Department of Defense |url=https://tioh.army.mil/Catalog/Heraldry.aspx?HeraldryId=16096&CategoryId=9316&grp=2 |url-status=live |archive-url=https://web.archive.org/web/20230916181026/https://tioh.army.mil/Catalog/Heraldry.aspx?HeraldryId=16096&CategoryId=9316&grp=2 |archive-date=2023-09-16 |access-date=2023-09-16 |website=[[United States Army Institute of Heraldry]]}}</ref>
| image = Pete Hegseth Official Portrait.jpg
| alt = 
| incumbent = [[Pete Hegseth]]
| acting = no
| incumbentsince = January 25, 2025
| department = [[United States Department of Defense]]<br/>[[Office of the Secretary of Defense]]
| style = Mr. Secretary (informal)<br/>[[The Honourable#United States|The Honorable]] (formal)
| status = 
| abbreviation = SecDef
| member_of = [[Cabinet of the United States|Cabinet]]<br/>[[United States National Security Council|National Security Council]]
| reports_to = [[President of the United States]]
| residence = 
| seat = [[The Pentagon]], [[Arlington County, Virginia|Arlington County]], [[Virginia]]
| nominator = 
| appointer = The [[President of the United States|President]]
| appointer_qualified = with [[United States Senate|Senate]] [[advice and consent]]
| termlength = No fixed term
| termlength_qualified = 
| constituting_instrument = {{UnitedStatesCode|10|113}}
| precursor = [[United States Secretary of War|Secretary of War]]<br/>[[United States Secretary of the Navy|Secretary of the Navy]]
| formation = {{start date|1947|9|17}}
| first = [[James Forrestal]]
| last = 
| abolished = 
| succession = [[United States presidential line of succession|Sixth]]<ref>{{cite web|url=https://www.law.cornell.edu/uscode/text/3/19|title=3 U.S. Code § 19 – Vacancy in offices of both President and Vice President; officers eligible to act|access-date=February 4, 2017|archive-date=December 26, 2018|archive-url=https://web.archive.org/web/20181226123834/https://www.law.cornell.edu/uscode/text/3/19|url-status=live}}</ref>
| unofficial_names = 
| deputy = [[United States Deputy Secretary of Defense|Deputy Secretary of Defense]]
| salary = [[Executive Schedule|Executive Schedule, level I]]<ref name="UnitedStatesCode|5|5312">{{UnitedStatesCode|5|5312}}</ref>
| website = {{URL|https://www.defense.gov/|defense.gov}}
}}
The '''United States secretary of defense''' ([[acronym]]: '''SecDef''') is the head of the [[United States Department of Defense]] (DoD), the [[United States federal executive departments|executive department]] of the [[United States Armed Forces|U.S. Armed Forces]], and is a high-ranking member of the [[Cabinet of the United States|federal cabinet]].<ref>{{UnitedStatesCode|10|113}}.</ref><ref name="5100.1">[[#5100.1|DoDD 5100.1]]: Enclosure 2: a</ref><ref name=":0">{{UnitedStatesCode|5|101}}.</ref> The secretary of defense's position of command and authority over the military is second only to that of the [[president of the United States]], who is the [[Powers of the president of the United States#Commander-in-chief|commander-in-chief]]. This position corresponds to what is generally known as a [[Defense Minister|defense minister]] in many other countries.<ref>{{Cite web|url=https://www.nato.int/cps/en/SID-C0FDE451-36F2483B/natolive/nato_countries.htm|title=NATO – member countries|website=[[NATO]]|access-date=January 4, 2012|archive-date=May 17, 2013|archive-url=https://web.archive.org/web/20130517140516/http://www.nato.int/cps/en/SID-C0FDE451-36F2483B/natolive/nato_countries.htm|url-status=live}}</ref> The president appoints the secretary of defense with the [[advice and consent]] of the [[United States Senate|Senate]], and is by custom a member of the Cabinet and by law a member of the [[United States National Security Council|National Security Council]].<ref>{{UnitedStatesCode|50|402}}.</ref>

To ensure [[civilian control of the military]], U.S. law provides that the secretary of defense cannot have served as an active-duty [[Officer (armed forces)|commissioned officer]] in the military in the preceding seven years except for [[general|generals]] and [[admiral|admirals]], who cannot have served on active duty within the previous ten years. Congress can legislatively waive this restriction<ref>See {{UnitedStatesCode|10|113}}.  The [[National Security Act of 1947]] originally required an interval of ten years after relief from active duty, which was reduced to seven years by Sec. 903(a) of the [[National Defense Authorization Act for the Fiscal Year 2008|2008 National Defense Authorization Act]]. In 1950 Congress passed special legislation (Pub. Law 81-788) to allow [[George C. Marshall]] to serve as Secretary of Defense while remaining a commissioned officer on the active list of the Army (Army regulations kept all [[General of the Army (United States)|five-star generals]] on active duty for life), but warned:

<blockquote>It is hereby expressed as the intent of the Congress that the authority granted by this Act is not to be construed as approval by the Congress of continuing appointments of military men to the office of Secretary of Defense in the future. It is hereby expressed as the sense of the Congress that after General Marshall leaves the office of Secretary of Defense, no additional appointments of military men to that office shall be approved.</blockquote>

[http://www.defenselink.mil/specials/secdef_histories/bios/marshall.htm Defenselink bio] {{Webarchive|url=https://web.archive.org/web/20081118005624/http://www.defenselink.mil/specials/secdef_histories/bios/marshall.htm|date=November 18, 2008}}, Retrieved February 8, 2010; and [http://www.marshallfoundation.org/about/chronology.html Marshall Foundation bio] {{Webarchive|url=https://web.archive.org/web/20110927043204/http://www.marshallfoundation.org/about/chronology.html|date=September 27, 2011}}, Retrieved February 8, 2010.</ref> and has done so three times, for [[George C. Marshall]], [[Jim Mattis|James N. Mattis]], and [[Lloyd Austin|Lloyd J. Austin III]].

Subject only to the orders of the president, the secretary of defense is in the [[chain of command]] and exercises [[command and control]], for both operational and administrative purposes, over all DoD-administered service branches {{snd}}the [[United States Army|Army]], [[United States Marine Corps|Marine Corps]], [[United States Navy|Navy]], [[United States Air Force|Air Force]], and [[United States Space Force|Space Force]]{{snd}}as well as the [[United States Coast Guard|Coast Guard]] when its command and control is transferred to the Department of Defense.<ref name="UnitedStatesCode|10|162">{{UnitedStatesCode|10|162}}</ref><ref name="JP1:II9-11">[[#JP1|Joint Publication 1]]: II-9, II-10 & II-11.</ref><ref>{{UnitedStatesCode|10|3011}}</ref><ref>{{UnitedStatesCode|10|5011}}</ref><ref>{{UnitedStatesCode|10|8011}}</ref> Only the secretary of defense (or the president or Congress) can authorize the transfer of operational control of forces between the three military departments ([[United States Department of the Army|Department of the Army]], [[United States Department of the Navy|the Navy]], and [[United States Department of the Air Force|the Air Force]]) and the eleven [[Unified Combatant Command]]s.<ref name="UnitedStatesCode|10|162"/> Because the secretary of defense is vested with legal powers that exceed those of any [[commissioned officer]], and is second only to the president in the military hierarchy, its incumbent has sometimes unofficially been referred to as "deputy commander-in-chief".<ref name="DoD50:11-52">[[#DoD50|Trask & Goldberg]]: pp.11 & 52</ref><ref name="SupCom:231">[[#SupCom|Cohen]]: p.231.</ref><ref>{{Cite web|url=https://www.americanprogress.org/issues/security/news/2006/10/31/2215/rumsfelds-management-failures/|title=Rumsfeld's Management Failures|last1=Korb|first1=Lawrence J.|last2=Ogden|first2=Pete|date=October 31, 2006|website=Center for American Progress|language=en-US|access-date=January 6, 2012|archive-date=October 22, 2017|archive-url=https://web.archive.org/web/20171022185308/https://www.americanprogress.org/issues/security/news/2006/10/31/2215/rumsfelds-management-failures/|url-status=live}}</ref> The [[chairman of the Joint Chiefs of Staff]] is the principal military adviser to the secretary of defense and the president; while the chairman may assist the secretary and president in their command functions, the chairman is not in the chain of command.<ref>{{UnitedStatesCode|10|152}}</ref>

The [[United States Secretary of State|secretary of state]], the [[United States Secretary of the Treasury|secretary of the treasury]], the secretary of defense, and the [[United States Attorney General|attorney general]] are generally regarded as the four most important (and are officially the four most senior and oldest) cabinet officials because of the size and importance of their respective departments.<ref>''Cabinets and Counselors: The President and the Executive Branch'' (1997). [[Congressional Quarterly]]. p. 87.</ref>

The current secretary of defense is [[Pete Hegseth]], who was nominated by President [[Donald Trump]] and was confirmed by the [[United States Senate|Senate]] on January 25, 2025.

== History ==
[[File:Seal of the United States National Military Establishment (1947–1949).png|thumb|Seal of the [[National Military Establishment]] (1947–1949)|left]]
An Army, Navy, and Marine Corps were established in 1775, in concurrence with the [[American Revolution]]. The [[United States Department of War|War Department]], headed by the [[United States Secretary of War|secretary of war]], was created by [[Act of Congress]] in 1789 and was responsible for both the Army and Navy until the founding of a separate [[United States Department of the Navy|Department of the Navy]] in 1798.
[[File:Associate Supreme Court Justice Potter Stewart Swearing Donald Rumsfeld in as Secretary of Defense at the Pentagon in Arlington, Virginia - NARA - 23898551.jpg|thumb|257x257px|[[Donald Rumsfeld]] is sworn in as Secretary of Defense by [[Associate Justice of the Supreme Court of the United States|Associate Supreme Court Justice]] [[Potter Stewart]] as [[President of the United States|U.S. President]] [[Gerald Ford|Gerald R. Ford]] and [[Chairman of the Joint Chiefs of Staff|Chairman of The Joint Chiefs of Staff]] General [[George Scratchley Brown|George S. Brown]] watch at [[The Pentagon]] on November 20, 1975.]]
Based on the experiences of [[World War II]], proposals were soon made on how to more effectively manage the large combined military establishment. The Army generally favored centralization while the Navy had institutional preferences for decentralization and the status quo. The resulting [[National Security Act of 1947]] was largely a compromise between these divergent viewpoints. It renamed the [[United States Department of War|Department of War]] the [[Department of the Army]], and added both it and the [[United States Department of the Navy|Department of the Navy]] to a newly established [[National Military Establishment]] (NME). The Act also separated the [[United States Army Air Forces|Army Air Forces]] from the Army to become its own branch of service, the [[United States Air Force]].

A new title was coined by the Act for the head of the NME: Secretary of Defense. At first, each of the service secretaries maintained cabinet status. The first secretary of defense, [[James Forrestal]], who in his previous capacity as the [[United States Secretary of the Navy|secretary of the Navy]] had opposed the creation of the new position, found it difficult to exercise authority over the other branches with the limited powers his office had at the time. To address this and other problems, the National Security Act was amended in 1949 to further consolidate the national defense structure in order to reduce [[interservice rivalry]], directly subordinate the [[United States Secretary of the Army|secretaries of the Army]], the Navy and the [[United States Secretary of the Air Force|Air Force]] to the secretary of defense in the chain of command, and rename the National Military Establishment as the Department of Defense, making it one [[Executive Department]]. The position of the [[United States Deputy Secretary of Defense|deputy secretary of defense]], the number two position in the department, was also created at this time.

The general trend since 1949 has been to further centralize management in the Department of Defense, elevating the status and authorities of civilian [[Office of the Secretary of Defense|OSD]] appointees and defense-wide organizations at the expense of the military departments and the services within them. The last major revision of the statutory framework concerning the position was done in the [[Goldwater–Nichols Department of Defense Reorganization Act of 1986]]. In particular, it elevated the status of joint service for commissioned officers, making it in practice a requirement before appointments to general officer and flag officer grades could be made.

As the secretary of defense is a civilian position intended to be independent of the active-duty leadership, a secretary is required to have been retired from service for at least seven (originally ten) years unless a waiver is approved by Congress.<ref>{{Cite web|last=Peters|first=Heidi M.|date=December 1, 2016|title=Waiver of Statutory Qualifications Relating to Prior Military Service of the Secretary of Defense|url=https://digital.library.unt.edu/ark:/67531/metadc958680/m1/1/|access-date=December 8, 2020|website=UNT Digital Library|language=en|archive-date=December 9, 2020|archive-url=https://web.archive.org/web/20201209062553/https://digital.library.unt.edu/ark:/67531/metadc958680/m1/1/|url-status=live}}</ref> Since the creation of the position in 1947, such a waiver has been approved only three times, for Army general [[George Marshall]] in 1950, Marine Corps General [[Jim Mattis]] in 2017, and retired Army general [[Lloyd Austin]] in 2021.<ref>{{Cite news|title=Why Generals Need Congressional Waivers To Become Defense Secretary|url=https://www.npr.org/2017/01/09/508902893/why-generals-need-congressional-waivers-to-become-defense-secretary|access-date=December 8, 2020|website=NPR.org|language=en|archive-date=December 10, 2020|archive-url=https://web.archive.org/web/20201210113310/https://www.npr.org/2017/01/09/508902893/why-generals-need-congressional-waivers-to-become-defense-secretary|url-status=live}}</ref><ref>{{Cite news|title=Lloyd Austin Receives Waiver Allowing Him to Become Defense Chief|url=https://www.wsj.com/articles/lawmakers-approve-waiver-allowing-lloyd-austin-to-become-defense-chief-11611269413|access-date=January 21, 2021|website=[[The Wall Street Journal]]|date=January 21, 2021|language=en|last1=Youssef|first1=Nancy A.|archive-date=January 22, 2021|archive-url=https://web.archive.org/web/20210122172905/https://www.wsj.com/articles/lawmakers-approve-waiver-allowing-lloyd-austin-to-become-defense-chief-11611269413|url-status=live}}</ref>

== Powers and functions ==
{{Main|Organizational structure of the United States Department of Defense}}

[[File:DoD Organization December 2013.jpg|thumb|upright=1.6|right|Department of Defense organizational chart (December 2013)]]

The secretary of defense, appointed by the [[President of the United States|president]] with the advice and consent of the [[United States Senate|Senate]], is by federal law ({{UnitedStatesCode|10|113}}) the head of the Department of Defense, "the principal assistant to the President in all matters relating to Department of Defense", and has "authority, direction and control over the Department of Defense". Because the [[Constitution of the United States|Constitution]] vests all military authority in [[United States Congress|Congress]] and the president, the statutory authority of the secretary of defense is derived from their constitutional authorities. Since it is impractical for either Congress or the president to participate in every piece of Department of Defense affairs, the secretary of defense and the secretary's subordinate officials generally exercise military authority.

As the head of DoD, all officials, employees and service members are "under" the secretary of defense. Some of those high-ranking officials, civil and military (outside of OSD and the Joint Staff) are: the [[United States Secretary of the Army|secretary of the Army]], [[United States Secretary of the Navy|secretary of the Navy]], and [[United States Secretary of the Air Force|secretary of the Air Force]], [[Chief of Staff of the United States Army|Army chief of staff]], [[Commandant of the United States Marine Corps|commandant of the Marine Corps]], [[Chief of Naval Operations|chief of naval operations]], [[Chief of Staff of the United States Air Force|Air Force chief of staff]], [[chief of space operations]], and [[chief of the National Guard Bureau]] and the combatant commanders of the [[Combatant Command]]s. All these high-ranking positions, civil and military, require Senate confirmation.

The Department of Defense is composed of the [[Office of the Secretary of Defense]] (OSD), the [[Joint Chiefs of Staff]] (JCS) and the [[Joint Staff]] (JS), [[Office of the Inspector General, U.S. Department of Defense|Office of the Inspector General]] (DODIG), the [[Unified Combatant Command|Combatant Commands]], the Military Departments ([[United States Department of the Army|Department of the Army]] (DA), [[United States Department of the Navy|Department of the Navy]] (DON) & [[United States Department of the Air Force|Department of the Air Force]] (DAF)), the [[List of Department of Defense agencies|Defense Agencies and DoD Field Activities]], the [[National Guard Bureau]] (NGB), and such other offices, agencies, activities, organizations, and commands established or designated by law, or by the president or by the secretary of defense.

Department of Defense Directive 5100.01 describes the organizational relationships within the department and is the foundational issuance for delineating the major functions of the department. The latest version, signed by former secretary of defense [[Robert Gates]] in December 2010, is the first major re-write since 1987.<ref name="DOMP">[[#DOMP|Department of Defense Directive 5100.01 Functions of the Department of Defense and Its Major Components]]</ref><ref name="5100.1:1">[[#5100.1|DoDD 5100.1]]: p.1.</ref>

=== Office of the Secretary of Defense ===
{{Main|Office of the Secretary of Defense}}
The secretary's principally civilian staff element is called the [[Office of the Secretary of Defense]] (OSD) and is composed of the [[United States Deputy Secretary of Defense|deputy secretary of defense]] (DEPSECDEF) and six under secretaries of defense in the fields of [[Under Secretary of Defense for Acquisition, Technology and Logistics|acquisition & sustainment]], [[Under Secretary of Defense for Research and Engineering|research & engineering]], [[Under Secretary of Defense (Comptroller)|comptroller/chief financial officer]], [[Under Secretary of Defense for Intelligence|intelligence]], [[Under Secretary of Defense for Personnel and Readiness|personnel & readiness]], and [[Under Secretary of Defense for Policy|policy]]; several [[Assistant Secretary of Defense|assistant secretaries of defense]]; other directors and the staffs under them.

The name of the principally military staff organization, organized under the chairman of the Joint Chiefs of Staff, is the [[Joint Staff]] (JS).

=== Awards and decorations ===
The [[Defense Distinguished Service Medal]] (DDSM), the [[Defense Superior Service Medal]] (DSSM), the [[Defense Meritorious Service Medal]] (DMSM), the [[Joint Service Commendation Medal]] (JSCM) and the [[Joint Service Achievement Medal]] (JSAM) are awarded, to military personnel for service in joint duty assignments, in the name of the secretary of defense. In addition, there is the [[Joint Meritorious Unit Award]] (JMUA), which is the only ribbon (as in non-medal) and unit award issued to joint DoD activities, also issued in the name of the secretary of defense.

The DDSM is analogous to the distinguished services medals issued by the military departments (i.e. [[Army Distinguished Service Medal]], [[Navy Distinguished Service Medal]] & [[Air Force Distinguished Service Medal]]), the DSSM corresponds to the [[Legion of Merit]], the DMSM to the [[Meritorious Service Medal (United States)|Meritorious Service Medal]], the JSCM to the service commendation medals, and the JSAM to the achievement medals issued by the services. While the approval authority for DSSM, DMSM, JSCM, JSAM and JMUA is delegated to inferior DoD officials: the DDSM can be awarded only by the secretary of defense.

Recommendations for the [[Medal of Honor]] (MOH), formally endorsed in writing by the secretary of the military department concerned and the [[chairman of the Joint Chiefs of Staff]], are processed through the [[Under Secretary of Defense for Personnel and Readiness|under secretary of defense for personnel and readiness]], and such recommendations be must approved by the secretary of defense before it can be handed over to the president, who is the final approval authority for the MOH, although it is awarded in the name of [[United States Congress|Congress]].

The secretary of defense, with the concurrence of the [[United States Secretary of State|secretary of state]], is the approval authority for the acceptance and wear of [[NATO]] medals issued by the [[Secretary General of NATO|secretary general of NATO]] and offered to the [[United States Permanent Representative to NATO|U.S. permanent representative to NATO]] in recognition of U.S. servicemembers who meet the eligibility criteria specified by NATO.<ref name="1348.33, V3:39">[[#13483, V3|DoDM 1348.33, Vol 3]]: p.39 (Enclosure 3)</ref>

=== Congressional committees ===
As the head of the department, the secretary of defense is the chief witness for the congressional committees with oversight responsibilities over the Department of Defense. The most important committees, with respect to the entire department, are the two authorizing committees, the [[United States Senate Committee on Armed Services|Senate Armed Services Committee]] (SASC) and the [[United States House Committee on Armed Services|House Armed Services Committee]] (HASC), and the two appropriations committees, the [[United States Senate Committee on Appropriations|Senate Appropriations Committee]] and the [[United States House Committee on Appropriations|House Appropriations Committee]].

For the DoD intelligence programs the [[United States Senate Select Committee on Intelligence|Senate Select Committee on Intelligence]] and the [[United States House Permanent Select Committee on Intelligence|House Permanent Select Committee on Intelligence]] have the principal oversight role.

=== National Security Council ===
The secretary of defense is a statutory member of the [[United States National Security Council|National Security Council]].<ref>{{UnitedStatesCode|50|402}}</ref> As one of the principals, the secretary along with the [[Vice President of the United States|vice president]], secretary of state and the [[Assistant to the President for National Security Affairs|assistant to the president for national security affairs]] participates in biweekly Principals Committee (PC) meetings, preparing and coordinating issues before they are brought before full NSC sessions chaired by the president.

=== Role in the military justice system ===
The secretary is one of only five or six civilians{{snd}}the others being the president, the three "service secretaries" (the [[secretary of the Army]], [[secretary of the Navy]], and [[secretary of the Air Force]]), and the [[Secretary of Homeland Security|secretary of homeland security]] (when the [[United States Coast Guard]] is under the [[United States Department of Homeland Security]] and has not been transferred to the [[United States Department of the Navy|Department of the Navy]] under the Department of Defense){{snd}}authorized to act as [[convening authority]] in the [[Uniform Code of Military Justice|military justice system]] for [[Courts-martial in the United States|General Courts-Martial]] ({{UnitedStatesCode|10|822}}: article 22, [[Uniform Code of Military Justice|UCMJ]]), Special Courts-Martial ({{UnitedStatesCode|10|823}}: article 23, UCMJ), and Summary Courts-Martial ({{UnitedStatesCode|10|824}}: article 24 UCMJ).

== Salary ==
The secretary of defense is a [[Executive Schedule#Level I|Level I position in the Executive Schedule]],<ref name="UnitedStatesCode|5|5312"/> thus earning a salary of [[US Dollar|US$]]246,400, as of October 2024.<ref name="Salary">{{cite web|url=https://www.opm.gov/policy-data-oversight/pay-leave/salaries-wages/salary-tables/pdf/2024/EX.pdf|archive-url=https://web.archive.org/web/20210123013351/https://www.opm.gov/policy-data-oversight/pay-leave/salaries-wages/salary-tables/pdf/2021/EX.pdf|archive-date=2021-01-23|url-status=live|title=Salary Table No. 2024-EX Rates of Basic Pay for the Executive Schedule (EX)}}</ref>

== List of secretaries of defense ==
The longest-serving secretary of defense is [[Robert McNamara]], who served for a total of 7{{spaces}}years, 39 days. Combining his two non-sequential services as the secretary of defense, the second-longest serving is [[Donald Rumsfeld]], who served just ten days fewer than McNamara. The second-longest unbroken tenure was Caspar Weinberger's, at 6{{spaces}}years, 306 days.

The shortest-serving secretary of defense is [[Elliot Richardson]], who served 114 days and then was appointed [[US Attorney General|U.S. attorney general]] amid the [[Richard Kleindienst|resignations]] of the [[Watergate Scandal]]. (This is not counting [[United States Deputy Secretary of Defense|deputy secretaries of defense]] [[William P. Clements]] and [[William Howard Taft IV]], who each served a few weeks as temporary/acting secretary of defense).

For precursors to this position prior to the establishment of the Department of Defense, see the lists of [[United States Secretary of the Navy#Executive Department, 1798–1949|secretaries of the Navy]] and [[United States Secretary of War#Secretary of War (1789–1947)|secretaries of war]] prior to 1947.

;Parties
{{legend2|{{party color|Democratic Party (United States)}}|[[Democratic Party (United States)|Democratic]]|border=1px solid #AAAAAA}}
{{legend2|{{party color|Republican Party (United States)}}|[[Republican Party (United States)|Republican]]|border=1px solid #AAAAAA}}
{{legend2|{{party color|Independent}}|[[Independent politician|Independent]] / Unknown|border=1px solid #AAAAAA}}

;Status
{{legend|#E6E6AA|Denotes an ''[[acting (law)|acting]] secretary of defense''|border=black}}

{|class="wikitable sortable"
!No.
!class=unsortable |Image
!Name
!Start
!End
!Duration
!colspan=2 |Party
!Home State
!colspan=2 |President(s)
|-
|1
|[[File:James Forrestal - SecOfDef.jpg|75px]]
|{{sortname|James|Forrestal}}<ref name="Historical Office James V. Forrestal">{{cite web |url=http://history.defense.gov/Multimedia/Biographies/Article-View/Article/571293/james-v-forrestal |title=James V. Forrestal – Harry S. Truman Administration |work=Office of the Secretary of Defense – Historical Office |access-date=February 7, 2017 |archive-date=August 14, 2017 |archive-url=https://web.archive.org/web/20170814095106/http://history.defense.gov/Multimedia/Biographies/Article-View/Article/571293/james-v-forrestal |url-status=live}}</ref>
|{{dts|September 17, 1947}}
|{{dts|March 28, 1949}}
|{{ayd|1947|9|17|1949|3|28}}
|style="background: {{party color|Democratic Party (United States)}};" |
|[[Democratic Party (United States)|Democratic]]
|{{Flag|New York}}
|rowspan=4 style="background: {{party color|Democratic Party (United States)}};" |
|rowspan=4 |{{sortname|Harry S.|Truman}}<br>{{small|(1945–1953)}}
|-
|2
|[[File:Louis Johnson official DoD photo.jpg|75px]]
|{{sortname|Louis A.|Johnson}}<ref name="Historical Office Louis A. Johnson">{{cite web |url=http://history.defense.gov/Multimedia/Biographies/Article-View/Article/571265/louis-a-johnson |title=Louis A. Johnson – Harry S. Truman Administration |work=Office of the Secretary of Defense – Historical Office |access-date=February 7, 2017 |archive-date=January 4, 2017 |archive-url=https://web.archive.org/web/20170104235947/http://history.defense.gov/Multimedia/Biographies/Article-View/Article/571265/louis-a-johnson |url-status=live}}</ref>
|{{dts|March 28, 1949}}
|{{dts|September 19, 1950}}
|{{ayd|1949|3|28|1950|9|19}}
|style="background: {{party color|Democratic Party (United States)}};" |
|[[Democratic Party (United States)|Democratic]]
|{{Flag|West Virginia}}
|-
|3
|[[File:General George C. Marshall, official military photo, 1946 (cropped).JPEG|75px]]
|{{sortname|George C.|Marshall}}<ref name="Historical Office George C. Marshall">{{cite web |url=http://history.defense.gov/Multimedia/Biographies/Article-View/Article/571266/george-c-marshall |title=George C. Marshall – Harry S. Truman Administration |work=Office of the Secretary of Defense – Historical Office |access-date=February 7, 2017 |archive-date=February 7, 2017 |archive-url=https://web.archive.org/web/20170207202422/http://history.defense.gov/Multimedia/Biographies/Article-View/Article/571266/george-c-marshall |url-status=live}}</ref>
|{{dts|September 21, 1950}}
|{{dts|September 12, 1951}}
|{{ayd|1950|9|21|1951|9|12}}
|style="background: {{party color|Independent (United States)}};" |
|[[Independent politician|Independent]]
|{{Flag|Pennsylvania}}
|-
|4
|[[File:Robert A. Lovett cph.3a47036.jpg|75px]]
|{{sortname|Robert A.|Lovett}}<ref name="Historical Office Robert A. Lovett">{{cite web |url=http://history.defense.gov/Multimedia/Biographies/Article-View/Article/571267/robert-a-lovett |title=Robert A. Lovett – Harry S. Truman Administration |work=Office of the Secretary of Defense – Historical Office |access-date=February 7, 2017 |archive-date=May 16, 2022 |archive-url=https://web.archive.org/web/20220516121458/https://history.defense.gov/Multimedia/Biographies/Article-View/Article/571267/robert-a-lovett |url-status=live}}</ref>
|{{dts|September 17, 1951}}
|{{dts|January 20, 1953}}
|{{ayd|1951|9|17|1953|1|20}}
|style="background: {{party color|Republican Party (United States)}};" |
|[[Republican Party (United States)|Republican]]
|{{Flag|New York}}
|-
|5
|[[File:Charles Wilson official DoD photo.jpg|75px]]
|{{sortname|Charles Erwin|Wilson}}<ref name="Historical Office Charles E. Wilson">{{cite web |url=http://history.defense.gov/Multimedia/Biographies/Article-View/Article/571268/charles-e-wilson |title=Charles E. Wilson – Dwight D. Eisenhower Administration |work=Office of the Secretary of Defense – Historical Office}}</ref>
|{{dts|January 28, 1953}}
|{{dts|October 8, 1957}}
|{{ayd|1953|1|28|1957|10|8}}
|style="background: {{party color|Republican Party (United States)}};" |
|[[Republican Party (United States)|Republican]]
|{{Flag|Michigan}}
|rowspan=3 style="background: {{party color|Republican Party (United States)}};" |
|rowspan=3 |{{sortname|Dwight D.|Eisenhower}}<br>{{small|(1953–1961)}}
|-
|6
|[[File:Neil McElroy official DoD photo.jpg|75px]]
|{{sortname|Neil H.|McElroy}}<ref name="Historical Office Neil H. McElroy">{{cite web |url=http://history.defense.gov/Multimedia/Biographies/Article-View/Article/571269/neil-h-mcelroy |title=Neil H. McElroy – Dwight D. Eisenhower Administration |work=Office of the Secretary of Defense – Historical Office |access-date=February 7, 2017 |archive-date=February 8, 2017 |archive-url=https://web.archive.org/web/20170208032824/http://history.defense.gov/Multimedia/Biographies/Article-View/Article/571269/neil-h-mcelroy |url-status=live}}</ref>
|{{dts|October 9, 1957}}
|{{dts|December 1, 1959}}
|{{ayd|1957|10|9|1959|12|1}}
|style="background: {{party color|Republican Party (United States)}};" |
|[[Republican Party (United States)|Republican]]
|{{Flag|Ohio}}
|-
|7
|[[File:Thomas S Gates Jr..jpg|75px]]
|{{sortname|Thomas S.|Gates Jr.}}<ref name="Historical Office Thomas S. Gates, Jr.">{{cite web |url=http://history.defense.gov/Multimedia/Biographies/Article-View/Article/571270/thomas-s-gates-jr |title=Thomas S. Gates, Jr. – Dwight D. Eisenhower Administration |work=Office of the Secretary of Defense – Historical Office}}</ref>
|{{dts|December 2, 1959}}
|{{dts|January 20, 1961}}
|{{ayd|1959|12|2|1961|1|20}}
|style="background: {{party color|Republican Party (United States)}};" |
|[[Republican Party (United States)|Republican]]
|{{Flag|Pennsylvania}}
|-
|8
|[[File:Robert McNamara official portrait.jpg|75px]]
|{{sortname|Robert|McNamara}}<ref name="Historical Office Robert S. McNamara">{{cite web |url=http://history.defense.gov/Multimedia/Biographies/Article-View/Article/571271/robert-s-mcnamara |title=Robert S. McNamara – John F. Kennedy / Lyndon Johnson Administration |work=Office of the Secretary of Defense – Historical Office |access-date=February 7, 2017 |archive-date=February 7, 2017 |archive-url=https://web.archive.org/web/20170207200914/http://history.defense.gov/Multimedia/Biographies/Article-View/Article/571271/robert-s-mcnamara |url-status=live}}</ref>
|{{dts|January 21, 1961}}
|{{dts|February 29, 1968}}
|{{ayd|1961|1|21|1968|2|29}}
|style="background: {{party color|Republican Party (United States)}};" |
|[[Republican Party (United States)|Republican]]
|{{Flag|Michigan}}
|style="background: {{party color|Democratic Party (United States)}};" |
|{{sortname|John F.|Kennedy}}<br>{{small|(1961–1963)}}<br>{{sortname|Lyndon B.|Johnson}}<br>{{small|(1963–1969)}}
|-
|9
|[[File:Clark Clifford photo portrait.jpg|75px]]
|{{sortname|Clark|Clifford}}<ref name="Historical Office Clark M. Gifford">{{cite web |url=http://history.defense.gov/Multimedia/Biographies/Article-View/Article/571292/clark-m-clifford |title=Clark M. Gifford – Lyndon Johnson Administration |work=Office of the Secretary of Defense – Historical Office |access-date=February 7, 2017 |archive-date=February 13, 2017 |archive-url=https://web.archive.org/web/20170213152713/http://history.defense.gov/Multimedia/Biographies/Article-View/Article/571292/clark-m-clifford |url-status=live}}</ref>
|{{dts|March 1, 1968}}
|{{dts|January 20, 1969}}
|{{ayd|1968|3|1|1969|1|20}}
|style="background: {{party color|Democratic Party (United States)}};" |
|[[Democratic Party (United States)|Democratic]]
|{{Flag|Maryland}}
|style="background: {{party color|Democratic Party (United States)}};" |
|{{sortname|Lyndon B.|Johnson}}<br>{{small|(1963–1969)}}
|-
|10
|[[File:Melvin Laird official photo.JPEG|75px]]
|{{sortname|Melvin|Laird}}<ref name="Historical Office Melvin R. Laird">{{cite web |url=http://history.defense.gov/Multimedia/Biographies/Article-View/Article/571291/melvin-r-laird |title=Melvin R. Laird – Richard Nixon Administration |work=Office of the Secretary of Defense – Historical Office |access-date=February 7, 2017 |archive-date=February 8, 2017 |archive-url=https://web.archive.org/web/20170208032715/http://history.defense.gov/Multimedia/Biographies/Article-View/Article/571291/melvin-r-laird |url-status=live}}</ref>
|{{dts|January 22, 1969}}
|{{dts|January 29, 1973}}
|{{ayd|1969|1|22|1973|1|29}}
|style="background: {{party color|Republican Party (United States)}};" |
|[[Republican Party (United States)|Republican]]
|{{Flag|Wisconsin}}
|rowspan=3 style="background: {{party color|Republican Party (United States)}};" |
|rowspan=3 |{{sortname|Richard|Nixon}}<br>{{small|(1969–1974)}}
|-
|11
|[[File:ElliotLeeRichardson.jpg|75px]]
|{{sortname|Elliot|Richardson}}<ref name="Historical Office Elliot L. Richardson">{{cite web |url=http://history.defense.gov/Multimedia/Biographies/Article-View/Article/571290/elliot-l-richardson |title=Elliot L. Richardson – Richard Nixon Administration |work=Office of the Secretary of Defense – Historical Office |access-date=February 7, 2017 |archive-date=February 7, 2017 |archive-url=https://web.archive.org/web/20170207202426/http://history.defense.gov/Multimedia/Biographies/Article-View/Article/571290/elliot-l-richardson |url-status=live}}</ref>
|{{dts|January 30, 1973}}
|{{dts|May 24, 1973}}
|{{ayd|1973|1|30|1973|5|24}}
|style="background: {{party color|Republican Party (United States)}};" |
|[[Republican Party (United States)|Republican]]
|{{Flag|Massachusetts}}
|- style="background:#e6e6aa;"
|–
|[[File:Clements Deputy DoD.jpg|75px]]
|{{sortname|Bill|Clements}}<br>{{small|Acting}}<ref name="Citizen Airmen">{{cite book |url=https://books.google.com/books?id=8Y3tmhPrl44C&q=William+P.+Clements,+Jr.+Acting+Secretary+of+Defense&pg=PA252 |last=Cantwell |first=Gerald T. |title=Citizen Airmen: A History of the Air Force Reserve 1946–1994 |year=1997 |publisher=DIANE Publishing |page=252 |isbn=9781428991620 |quote=In June 1973, Representative O. C. Fisher complained to William P. Clements, Jr., acting Secretary of Defense, that the authority, responsibility, and, consequently, effectiveness of the chiefs of the various reserve components seemed to be eroding.}}</ref>
|{{dts|May 24, 1973}}
|{{dts|July 2, 1973}}
|{{ayd|1973|5|24|1973|7|2}}
|style="background: {{party color|Republican Party (United States)}};" |
|[[Republican Party (United States)|Republican]]
| rowspan="" |{{Flag|Texas}}
|-
|12
|rowspan= |[[File:James Schlesinger official DoD photo BW (cropped).jpg|75px]]
|rowspan= |{{sortname|James R.|Schlesinger}}<ref name="Historical Office James R. Schlesinger">{{cite web |url=http://history.defense.gov/Multimedia/Biographies/Article-View/Article/571289/james-r-schlesinger |title=James R. Schlesinger – Richard Nixon / Gerald Ford Administration |work=Office of the Secretary of Defense – Historical Office |access-date=February 7, 2017 |archive-date=February 8, 2017 |archive-url=https://web.archive.org/web/20170208032933/http://history.defense.gov/Multimedia/Biographies/Article-View/Article/571289/james-r-schlesinger |url-status=live}}</ref>
|rowspan= |{{dts|July 2, 1973}}
|rowspan= |{{dts|November 19, 1975}}
|rowspan= |{{ayd|1973|7|2|1975|11|19}}
|style="background: {{party color|Republican Party (United States)}};" |
|rowspan= |[[Republican Party (United States)|Republican]]
|rowspan= |{{Flag|Virginia}}
|style="background: {{party color|Republican Party (United States)}};" |
|{{sortname|Richard|Nixon}}<br>{{small|(1969–1974)}}<br>{{sortname|Gerald|Ford}}<br>{{small|(1974–1977)}}
|-
|13
|[[File:Rumsfeld Ford admin Secretary of Defense.jpg|75px]]
|{{sortname|Donald|Rumsfeld}}<ref name="Historical Office Rumsfeld Ford Administration">{{cite web |url=http://history.defense.gov/Multimedia/Biographies/Article-View/Article/571288/donald-h-rumsfeld |title=Donald H. Rumsfeld – Gerald Ford Administration |work=Office of the Secretary of Defense – Historical Office |access-date=February 7, 2017 |archive-date=February 8, 2017 |archive-url=https://web.archive.org/web/20170208032709/http://history.defense.gov/Multimedia/Biographies/Article-View/Article/571288/donald-h-rumsfeld |url-status=live}}</ref>
|{{dts|November 20, 1975}}
|{{dts|January 20, 1977}}
|{{ayd|1975|11|20|1977|1|20}}
|style="background: {{party color|Republican Party (United States)}};" |
|[[Republican Party (United States)|Republican]]
|{{Flag|Illinois}}
|rowspan=1 style="background: {{party color|Republican Party (United States)}};" |
|rowspan= |{{sortname|Gerald|Ford}}<br>{{small|(1974–1977)}}
|-
|14
|[[File:Harold Brown photo portrait standing.jpg|75px]]
|{{sortname|Harold|Brown|dab=Secretary of Defense}}<ref name="Historical Office Harold Brown">{{cite web |url=http://history.defense.gov/Multimedia/Biographies/Article-View/Article/571287/harold-brown |title=Harold Brown – James Carter Administration |work=Office of the Secretary of Defense – Historical Office |access-date=February 7, 2017 |archive-date=November 22, 2018 |archive-url=https://web.archive.org/web/20181122143700/https://history.defense.gov/Multimedia/Biographies/Article-View/Article/571287/harold-brown |url-status=live}}</ref>
|{{dts|January 20, 1977}}
|{{dts|January 20, 1981}}
|{{ayd|1977|1|20|1981|1|20}}
|style="background: {{party color|Democratic Party (United States)}};" |
|[[Democratic Party (United States)|Democratic]]
|{{Flag|California}}
|style="background: {{party color|Democratic Party (United States)}};" |
|{{sortname|Jimmy|Carter}}<br>{{small|(1977–1981)}}
|-
|15
|[[File:Caspar Weinberger official photo.jpg|75px]]
|{{sortname|Caspar|Weinberger}}<ref name="Historical Office Caspar W. Weinberger">{{cite web |url=http://history.defense.gov/Multimedia/Biographies/Article-View/Article/571286/caspar-w-weinberger |title=Caspar W. Weinberger – Ronald Reagan Administration |work=Office of the Secretary of Defense – Historical Office |access-date=February 7, 2017 |archive-date=October 22, 2023 |archive-url=https://web.archive.org/web/20231022023308/https://history.defense.gov/Multimedia/Biographies/Article-View/Article/571286/caspar-w-weinberger |url-status=live}}</ref>
|{{dts|January 21, 1981}}
|{{dts|November 23, 1987}}
|{{ayd|1981|1|21|1987|11|23}}
|style="background: {{party color|Republican Party (United States)}};" |
|[[Republican Party (United States)|Republican]]
|{{Flag|California}}
|rowspan=2 style="background: {{party color|Republican Party (United States)}};" |
|rowspan=2 |{{sortname|Ronald|Reagan}}<br>{{small|(1981–1989)}}
|-
|16
|[[File:Frank Carlucci official portrait.JPEG|75px]]
|{{sortname|Frank|Carlucci}}<ref name="Historical Office Frank C. Carlucci">{{cite web |url=http://history.defense.gov/Multimedia/Biographies/Article-View/Article/571285/frank-c-carlucci |title=Frank C. Carlucci – Ronald Reagan Administration |work=Office of the Secretary of Defense – Historical Office |access-date=February 7, 2017 |archive-date=February 7, 2017 |archive-url=https://web.archive.org/web/20170207195410/http://history.defense.gov/Multimedia/Biographies/Article-View/Article/571285/frank-c-carlucci |url-status=live}}</ref>
|{{dts|November 23, 1987}}
|{{dts|January 20, 1989}}
|{{ayd|1987|11|23|1989|1|20}}
|style="background: {{party color|Republican Party (United States)}};" |
|[[Republican Party (United States)|Republican]]
|{{Flag|Virginia}}
|-
|style="background:#e6e6aa;" |–
|style="background:#e6e6aa;" |[[File:William Howard Taft IV, Deptuty Secretary of Defense, official portrait.JPEG|75px]]
|style="background:#e6e6aa;" |{{sortname|William Howard|Taft IV}}<br>{{small|Acting}}<ref>{{cite web |url=http://www.whs.mil/library/Key47-04/II.pdf |title=II. Secretaries of Defense |publisher=Washington Headquarters Services – Pentagon Digital Library |pages=9 |quote=(Deputy Secretary of Defense William H. Taft served as acting secretary of defense from 20 January 1989 until 21 March 1989). |access-date=February 8, 2017 |archive-date=February 11, 2017 |archive-url=https://web.archive.org/web/20170211081016/http://www.whs.mil/library/Key47-04/II.pdf |url-status=dead}}</ref>
|style="background:#e6e6aa;" |{{dts|January 20, 1989}}
|style="background:#e6e6aa;" |{{dts|March 21, 1989}}
|style="background:#e6e6aa;" |{{ayd|1989|1|20|1989|3|21}}
|style="background: {{party color|Republican Party (United States)}};" |
|style="background:#e6e6aa;" |[[Republican Party (United States)|Republican]]
|style="background:#e6e6aa;" |{{Flag|Ohio}}
|rowspan=2 style="background: {{party color|Republican Party (United States)}};" |
|rowspan=2 |{{sortname|George H. W.|Bush}}<br>{{small|(1989–1993)}}
|-
|17
|[[File:Secretary of Defense Richard B. Cheney, official portrait (cropped).jpg|75px]]
|{{sortname|Dick|Cheney}}<ref name="Historical Office Richard B. Cheney">{{cite web |url=http://history.defense.gov/Multimedia/Biographies/Article-View/Article/571284/richard-b-cheney |title=Richard B. Cheney – George H.W. Bush Administration |work=Office of the Secretary of Defense – Historical Office |access-date=February 7, 2017 |archive-date=June 14, 2019 |archive-url=https://web.archive.org/web/20190614191740/https://history.defense.gov/Multimedia/Biographies/Article-View/Article/571284/richard-b-cheney |url-status=live}}</ref>
|{{dts|March 21, 1989}}
|{{dts|January 20, 1993}}
|{{ayd|1989|3|21|1993|1|20}}
|style="background: {{party color|Republican Party (United States)}};" |
|[[Republican Party (United States)|Republican]]
|{{Flag|Wyoming}}
|-
|18
|[[File:Les Aspin official DoD photo.jpg|75px]]
|{{sortname|Les|Aspin}}<ref name="Historical Office Leslie Aspin">{{cite web |url=http://history.defense.gov/Multimedia/Biographies/Article-View/Article/571283/leslie-aspin |title=Leslie Aspin – William J. Clinton Administration |publisher=Office of the Secretary of Defense – Historical Office |access-date=February 7, 2017 |archive-date=July 8, 2023 |archive-url=https://web.archive.org/web/20230708115119/https://history.defense.gov/Multimedia/Biographies/Article-View/Article/571283/leslie-aspin |url-status=live}}</ref><ref name=DODKO>[[#DODKO|Department of Defense Key Officials September 1947 – February 2019]]</ref><ref name="CQAlmanac1993">{{cite web |url=https://library.cqpress.com/cqalmanac/document.php?id=cqal93-1106289 |title=Les Aspin Serves One Year As Defense Secretary |access-date=March 18, 2019 |archive-date=December 8, 2023 |archive-url=https://web.archive.org/web/20231208134400/https://library.cqpress.com/cqalmanac/login.php?requested=%2Fcqalmanac%2Fdocument.php%3Fid%3Dcqal93-1106289 |url-status=live}}</ref>
|{{dts|January 20, 1993}}
|{{dts|February 3, 1994}}
|{{ayd|1993|1|20|1994|2|3}}
|style="background: {{party color|Democratic Party (United States)}};" |
|[[Democratic Party (United States)|Democratic]]
|{{Flag|Wisconsin}}
|rowspan=3 style="background: {{party color|Democratic Party (United States)}};" |
|rowspan=3 |{{sortname|Bill|Clinton}}<br>{{small|(1993–2001)}}
|-
|19
|[[File:William Perry official DoD photo (retouched).jpg|75px]]
|{{sortname|William|Perry|William J. Perry}}<ref name="Historical Office William J. Perry">{{cite web |url=http://history.defense.gov/Multimedia/Biographies/Article-View/Article/571282/william-j-perry |title=William J. Perry – William J. Clinton Administration |publisher=Office of the Secretary of Defense – Historical Office |access-date=February 7, 2017 |archive-date=April 22, 2021 |archive-url=https://web.archive.org/web/20210422203733/https://history.defense.gov/Multimedia/Biographies/Article-View/Article/571282/william-j-perry |url-status=live}}</ref><ref name=DODKO/><ref>{{cite web |url=http://www.whs.mil/library/Key47-04/II.pdf |title=II. Secretaries of Defense |publisher=Washington Headquarters Services – Pentagon Digital Library |pages=10 |quote=Sworn in as secretary of defense on 3 February 1994 and served until 24 January 1997. |access-date=February 8, 2017 |archive-date=February 11, 2017 |archive-url=https://web.archive.org/web/20170211081016/http://www.whs.mil/library/Key47-04/II.pdf |url-status=dead}}</ref>
|{{dts|February 3, 1994}}
|{{dts|January 24, 1997}}
|{{ayd|1994|2|3|1997|1|24}}
|style="background: {{party color|Democratic Party (United States)}};" |
|[[Democratic Party (United States)|Democratic]]
|{{Flag|Pennsylvania}}
|-
|20
|[[File:William Cohen, official portrait (cropped).jpg|75px]]
|{{sortname|William|Cohen}}<ref name="Historical Office William S. Cohen">{{cite web |url=http://history.defense.gov/Multimedia/Biographies/Article-View/Article/571281/william-s-cohen |title=William S. Cohen – William J. Clinton Administration |publisher=Office of the Secretary of Defense – Historical Office |access-date=February 7, 2017 |archive-date=September 19, 2023 |archive-url=https://web.archive.org/web/20230919223432/https://history.defense.gov/Multimedia/Biographies/Article-View/Article/571281/william-s-cohen |url-status=live}}</ref>
|{{dts|January 24, 1997}}
|{{dts|January 20, 2001}}
|{{ayd|1997|1|24|2001|1|20}}
|style="background: {{party color|Republican Party (United States)}};" |
|[[Republican Party (United States)|Republican]]
|{{Flag|Maine}}
|-
|21
|[[File:Rumsfeld1 (cropped).jpg|75px]]
|{{sortname|Donald|Rumsfeld}}<ref name="Historical Office Rumsfeld Bush Administration">{{cite web |url=http://history.defense.gov/Multimedia/Biographies/Article-View/Article/571280/donald-h-rumsfeld |title=Donald H. Rumsfeld – George W. Bush Administration |publisher=Office of the Secretary of Defense – Historical Office |access-date=February 7, 2017 |archive-date=February 7, 2017 |archive-url=https://web.archive.org/web/20170207202420/http://history.defense.gov/Multimedia/Biographies/Article-View/Article/571280/donald-h-rumsfeld |url-status=live}}</ref>
|{{dts|January 20, 2001}}
|{{dts|December 18, 2006}}
|{{ayd|2001|1|20|2006|12|18}}<br>{{small|(7 years, 29 days total)}}
|style="background: {{party color|Republican Party (United States)}};" |
|[[Republican Party (United States)|Republican]]
|{{Flag|Illinois}}
|rowspan=1 style="background: {{party color|Republican Party (United States)}};" |
|rowspan= |{{sortname|George W.|Bush}}<br>{{small|(2001–2009)}}
|-
|rowspan=2 |22
|rowspan=2 |[[File:Robert Gates, official DoD photo portrait, 2006 (cropped).jpg|75px]]
|rowspan=2 |{{sortname|Robert|Gates}}<ref name="Historical Office Robert M. Gates">{{cite web |url=http://history.defense.gov/Multimedia/Biographies/Article-View/Article/571279/robert-m-gates |title=Robert M. Gates – George W. Bush / Barack Obama Administration |publisher=Office of the Secretary of Defense – Historical Office |access-date=February 7, 2017 |archive-date=February 7, 2017 |archive-url=https://web.archive.org/web/20170207114027/http://history.defense.gov/Multimedia/Biographies/Article-View/Article/571279/robert-m-gates |url-status=live}}</ref><ref name=DODKO/>
|rowspan=2 |{{dts|December 18, 2006}}
|rowspan=2 |{{dts|June 30, 2011}}
|rowspan=2 |{{ayd|2006|12|18|2011|6|30}}
|rowspan=2 style="background: {{party color|Republican Party (United States)}};" |
|rowspan=2 |[[Republican Party (United States)|Republican]]
|rowspan=2 |{{Flag|Texas}}
|rowspan=1 style="background: {{party color|Republican Party (United States)}};" |
|rowspan= |{{sortname|George W.|Bush}}<br>{{small|(2001–2009)}}
|-
|rowspan=1 style="background: {{party color|Democratic Party (United States)}};" |
|{{sortname|Barack|Obama}}<br>{{small|(2009–2017)}}
|-
|23
|[[File:Leon Panetta, official DoD photo portrait, 2011 (cropped).jpg|75px]]
|{{sortname|Leon|Panetta}}<ref name="Historical Office Leon E. Panetta">{{cite web |url=http://history.defense.gov/Multimedia/Biographies/Article-View/Article/571278/leon-e-panetta |title=Leon E. Panetta – Barack Obama Administration |publisher=Office of the Secretary of Defense – Historical Office |access-date=February 7, 2017 |archive-date=February 7, 2017 |archive-url=https://web.archive.org/web/20170207193905/http://history.defense.gov/Multimedia/Biographies/Article-View/Article/571278/leon-e-panetta |url-status=live}}</ref>
|{{dts|July 1, 2011}}
|{{dts|February 26, 2013}}
|{{ayd|2011|7|1|2013|2|26}}
|style="background: {{party color|Democratic Party (United States)}};" |
|[[Democratic Party (United States)|Democratic]]
|{{Flag|California}}
|rowspan=3 style="background: {{party color|Democratic Party (United States)}};" |
|rowspan=3 |{{sortname|Barack|Obama}}<br>{{small|(2009–2017)}}
|-
|24
|[[File:Chuck Hagel Defense portrait (cropped).jpg|75px]]
|{{sortname|Chuck|Hagel}}<ref name="Historical Office Chuck Hagel">{{cite web |url=http://history.defense.gov/Multimedia/Biographies/Article-View/Article/571277/chuck-hagel |title=Chuck Hagel – Barack Obama Administration |publisher=Office of the Secretary of Defense – Historical Office |access-date=February 7, 2017 |archive-date=February 25, 2017 |archive-url=https://web.archive.org/web/20170225153110/http://history.defense.gov/Multimedia/Biographies/Article-View/Article/571277/chuck-hagel |url-status=live}}</ref>
|{{dts|February 27, 2013}}
|{{dts|February 17, 2015}}
|{{ayd|2013|2|27|2015|2|17}}
|style="background: {{party color|Republican Party (United States)}};" |
|[[Republican Party (United States)|Republican]]
|{{Flag|Nebraska}}
|-
|25
|[[File:Ash Carter DOD Secretary Portrait (cropped).jpg|75px]]
|{{sortname|Ash|Carter}}<ref name="Historical Office Ashton B. Carter">{{cite web |url=http://history.defense.gov/Multimedia/Biographies/Article-View/Article/571296/ashton-b-carter |title=Ashton B. Carter – Barack Obama Administration |publisher=Office of the Secretary of Defense – Historical Office|access-date=February 7, 2017 |archive-date=February 7, 2017 |archive-url=https://web.archive.org/web/20170207195408/http://history.defense.gov/Multimedia/Biographies/Article-View/Article/571296/ashton-b-carter |url-status=live}}</ref><ref name=DODKO/>
|{{dts|February 17, 2015}}
|{{dts|January 20, 2017}}
|{{ayd|2015|2|17|2017|1|20}}
|style="background: {{party color|Democratic Party (United States)}};" |
|[[Democratic Party (United States)|Democratic]]
|{{Flag|Massachusetts}}
|-
|26
|[[File:James Mattis official photo (cropped).jpg|75px]]
|{{sortname|Jim|Mattis}}<ref name="Historical Office James N. Mattis">{{cite web |url=http://history.defense.gov/Multimedia/Biographies/Article-View/Article/1059855/james-n-mattis |title=James N. Mattis – Donald Trump Administration |publisher=Office of the Secretary of Defense – Historical Office |access-date=February 7, 2017 |archive-date=February 12, 2017 |archive-url=https://web.archive.org/web/20170212142655/http://history.defense.gov/Multimedia/Biographies/Article-View/Article/1059855/james-n-mattis |url-status=live}}</ref>
|{{dts|January 20, 2017}}
|{{dts|January 1, 2019}}
|{{ayd|2017|1|20|2018|12|31}}
|style="background: {{party color|Independent (United States)}};" |
|[[Independent politician|Independent]]
|{{Flag|Washington}}
|rowspan=6 style="background: {{party color|Republican Party (United States)}};" |
|rowspan=6 |{{sortname|Donald|Trump}}<br>{{small|(2017–2021)}}
|- style="background:#e6e6aa;"
|–
|[[File:Patrick Shanahan (cropped).jpg|75px]]
|{{sortname|Patrick M.|Shanahan}}<br>{{small|Acting}}<ref>{{cite web |website=Congress.gov |publisher=Library of Congress |title=PN583 – Patrick M. Shanahan – Department of Defense |date=July 18, 2017 |access-date=January 1, 2019 |url=https://www.congress.gov/nomination/115th-congress/583 |archive-date=January 7, 2019 |archive-url=https://web.archive.org/web/20190107222159/https://www.congress.gov/nomination/115th-congress/583 |url-status=live}}</ref>
|{{dts|January 1, 2019}}
|{{dts|June 23, 2019}}
|{{ayd|2019|1|1|2019|6|23}}
|style="background: {{party color|Independent (United States)}};" |
|[[Independent politician|Independent]]
|{{Flag|Washington}}
|- style="background:#e6e6aa;"
|–
|[[File:Mark T. Esper (cropped).jpg|75px]]
|{{sortname|Mark|Esper}}<br>{{small|Acting}}<ref name=esperbio>{{cite web |url=https://dod.defense.gov/About/Biographies/Biography-View/Article/1378166/dr-mark-t-esper |title=Dr. Mark T. Esper – Acting Secretary of Defense |date=June 24, 2019 |publisher=United States Department of Defense |access-date=June 24, 2019 |archive-date=August 2, 2019 |archive-url=https://web.archive.org/web/20190802075402/https://dod.defense.gov/About/Biographies/Biography-View/Article/1378166/dr-mark-t-esper |url-status=live}}</ref>
|{{dts|June 24, 2019}}
|{{dts|July 15, 2019}}
|{{ayd|2019|6|24|2019|7|15}}
|style="background: {{party color|Republican Party (United States)}};" |
|[[Republican Party (United States)|Republican]]
|{{Flag|Virginia}}
|- style="background:#e6e6aa;"
|–
|[[File:Richard V. Spencer official photo (cropped).jpg|75px]]
|{{sortname|Richard V.|Spencer}}<br>{{small|Acting}}<ref name=SpencerActingSecDef>{{cite web |url=https://news.usni.org/2019/07/15/letter-from-acting-secretary-of-defense-richard-v-spencer-to-pentagon |title=Letter from Acting Secretary of Defense Richard V. Spencer to Pentagon |date=July 15, 2019 |publisher=USNI News |access-date=July 16, 2019 |archive-date=July 23, 2019 |archive-url=https://web.archive.org/web/20190723022439/https://news.usni.org/2019/07/15/letter-from-acting-secretary-of-defense-richard-v-spencer-to-pentagon |url-status=live}}</ref>
|{{dts|July 15, 2019}}
|{{dts|July 23, 2019}}
|{{ayd|2019|7|15|2019|7|23}}
|style="background: {{party color|Republican Party (United States)}};" |
|[[Republican Party (United States)|Republican]]
|{{Flag|Wyoming}}
|-
|27
|[[File:Dr. Mark T. Esper – Acting Secretary of Defense (cropped).jpg|75px]]
|{{sortname|Mark|Esper}}<ref name=esperbio/>
|{{dts|July 23, 2019}}
|{{dts|November 9, 2020}}
|{{ayd|2019|7|23|2020|11|9}}
|style="background: {{party color|Republican Party (United States)}};" |
|[[Republican Party (United States)|Republican]]
|{{Flag|Virginia}}
|- style="background:#e6e6aa;"
|–
|[[File:Christopher C. Miller official portrait (cropped).jpg|75px]]
|{{sortname|Christopher C.|Miller}}<br>{{small|Acting}}<ref name=esperbio/>
|{{dts|November 9, 2020}}
|{{dts|January 20, 2021}}
|{{ayd|2020|11|9|2021|1|20}}
|style="background: {{party color|Republican Party (United States)}};" |
|[[Republican Party (United States)|Republican]]
|{{Flag|Iowa}}
|-
|style="background:#e6e6aa;" |–
|style="background:#e6e6aa;" |[[File:David L. Norquist – Deputy Secretary of Defense (cropped).jpg|75px]]
|style="background:#e6e6aa;" |{{sortname|David|Norquist}}<br>{{small|Acting}}<ref>{{cite web |url=https://thehill.com/policy/defense/535078-trump-administration-official-norquist-sworn-in-as-acting-pentagon-chief |title=Trump administration official Norquist sworn in as acting Pentagon chief |work=[[The Hill (newspaper)|The Hill]] |date=January 20, 2021 |access-date=January 20, 2021 |url-status=live |archive-url=https://web.archive.org/web/20210120225420/https://thehill.com/policy/defense/535078-trump-administration-official-norquist-sworn-in-as-acting-pentagon-chief |archive-date=January 20, 2021}}</ref>
|style="background:#e6e6aa;" |{{dts|January 20, 2021}}
|style="background:#e6e6aa;" |{{dts|January 22, 2021}}
|style="background:#e6e6aa;" |{{ayd|2021|1|20|2021|1|22}}
|style="background: {{party color|Republican Party (United States)}};" |
|style="background:#e6e6aa;" |[[Republican Party (United States)|Republican]]
|style="background:#e6e6aa;" |{{Flag|Massachusetts}}
|rowspan=2 style="background: {{party color|Democratic Party (United States)}};" |
|rowspan=2 |{{sortname|Joe|Biden}}<br>{{small|(2021–2025)}}
|-
|28
|[[File:Secretary of Defense Lloyd Austin, official portrait, 2023 (cropped).jpg|75px]]
|{{sortname|Lloyd|Austin}}<ref>{{cite web |url=https://edition.cnn.com/2021/01/22/politics/lloyd-austin-senate-vote-confirmation/index.html |title=Senate confirms Lloyd Austin to be first Black defense secretary |website=cnn.com |date=January 22, 2021 |access-date=January 22, 2021 |url-status=live |archive-url=https://web.archive.org/web/20210122162426/https://edition.cnn.com/2021/01/22/politics/lloyd-austin-senate-vote-confirmation/index.html |archive-date=January 22, 2021}}</ref>
|{{dts|January 22, 2021}}
|{{dts|January 20, 2025}}
|{{ayd|2021|1|22|2025|1|20}}
|style="background: {{party color|Independent (United States)}};" |
|[[Independent politician|Independent]]
|{{Flag|Georgia (U.S. state)|name=Georgia}}
|-
|style="background:#e6e6aa;" |–
|style="background:#e6e6aa;" |[[File:Robert Salesses in 2005 (cropped).jpg|75px]]
|style="background:#e6e6aa;" |{{sortname|Robert G.|Salesses}}<br>{{small|Acting}}
|style="background:#e6e6aa;" |{{dts|January 20, 2025}}
|style="background:#e6e6aa;" |{{dts|January 25, 2025}}
|style="background:#e6e6aa;" |{{ayd|2025|1|20|2025|1|25}}
|style="background: {{party color|Independent (United States)}};" |
|style="background:#e6e6aa;" |[[Independent politician|Independent]]
|style="background:#e6e6aa;" |{{Flag|Rhode Island}}
|rowspan=2 style="background: {{party color|Republican Party (United States)}};" |
|rowspan=2 |{{sortname|Donald|Trump}}<br>{{small|(2025–present)}}
|-
|29
|[[File:Secretary of Defense Pete Hegseth official portrait (cropped).jpg|75px]]
|{{sortname|Pete|Hegseth}}
|{{dts|January 25, 2025}}
|Incumbent
|{{ayd|2025|1|25}}
|style="background: {{party color|Republican Party (United States)}};" |
|[[Republican Party (United States)|Republican]]
|{{Flag|Tennessee}}
|}

== Succession ==
=== Presidential succession ===
The secretary of defense is sixth in the [[United States presidential line of succession|presidential line of succession]], following the [[United States Secretary of the Treasury|secretary of the treasury]] and preceding the [[United States Attorney General|attorney general]].<ref>{{UnitedStatesCode|3|19}}.</ref>

=== Secretary succession ===
On December 10, 2020, President Donald Trump modified the order of succession for the office of Secretary of Defense in Executive Order 13963. The order of succession is:<ref>{{Cite web|title=Executive Order on Providing an Order of Succession within the Department of Defense|url=https://www.federalregister.gov/documents/2020/12/15/2020-27739/providing-an-order-of-succession-within-the-department-of-defense|date=December 10, 2020|language=en-US|access-date=January 9, 2022|archive-date=December 15, 2020|archive-url=https://web.archive.org/web/20201215165424/https://www.federalregister.gov/documents/2020/12/15/2020-27739/providing-an-order-of-succession-within-the-department-of-defense|url-status=live}}</ref>
{| class="wikitable"
|+
!#
!Office
|-
|1
|[[United States Deputy Secretary of Defense|Deputy Secretary of Defense]]
|-
|2*
|[[United States Secretary of the Army|Secretary of the Army]]<br>[[United States Secretary of the Navy|Secretary of the Navy]]<br>[[United States Secretary of the Air Force|Secretary of the Air Force]]
|-
|3
|[[Under Secretary of Defense for Policy]]
|-
|4
|[[Under Secretary of Defense for Intelligence|Under Secretary of Defense for Intelligence and Security]]
|-
| -
|[[Chief Management Officer of the Department of Defense]]**
|-
|5
|[[Under Secretary of Defense for Acquisition and Sustainment]]
|-
|6
|[[Under Secretary of Defense for Research and Engineering]]
|-
|7
|[[Under Secretary of Defense (Comptroller)]]
|-
|8
|[[Under Secretary of Defense for Personnel and Readiness]]
|-
|9
|[[Under Secretary of Defense for Policy#Principal Deputy|Deputy Under Secretary of Defense for Policy]]
|-
|10
|Deputy Under Secretary of Defense for Intelligence and Security;
|-
|11
|Deputy Under Secretary of Defense for Acquisition and Sustainment;
|-
|12
|Deputy Under Secretary of Defense for Research and Engineering
|-
|13
|Deputy Under Secretary of Defense (Comptroller)
|-
|14
|Deputy Under Secretary of Defense for Personnel and Readiness
|-
|15*
|[[General Counsel of the Department of Defense]]<br>[[United States Assistant Secretary of Defense|Assistant Secretaries of Defense]]<br>Director of Cost Assessment and Program Evaluation<br>Director of Operational Test and Evaluation<br>Chief Information Officer of the Department of Defense
|-
|16*
|[[United States Under Secretary of the Army|Under Secretary of the Army]]<br>[[United States Under Secretary of the Navy|Under Secretary of the Navy]]<br>[[United States Under Secretary of the Air Force|Under Secretary of the Air Force]]
|-
|17*
|[[Assistant Secretary of the Army|Assistant Secretaries of the Army]]<br>[[Assistant Secretary of the Navy|Assistant Secretaries of the Navy]]<br>[[Assistant Secretary of the Air Force|Assistant Secretaries of the Air Force]]<br>[[General Counsel of the Army]]<br>[[General Counsel of the Navy]]<br>[[General Counsel of the Air Force]]
|-
|
|*Order of Succession is determined by the seniority of officials in their role.{{efn|According to the Executive Order precedence states – in layman’s terms – that appointees designated the same succession number are determined by the order in which the date they were appointed (senate confirmed) to their position. However appointees designated the same succession number and have the same appointment (senate confirmed) date shall be determined  by the order in which they have taken the oath to serve in that office.}} 
|-
|
|**Office dissolved on January 1, 2021.{{efn|Congress disestablished the CMO position with the passage of the [[William M. (Mac) Thornberry National Defense Authorization Act for Fiscal Year 2021]] effective 1 January 2021.<ref>{{cite web |url=https://www.defense.gov/Newsroom/Releases/Release/Article/2468186/department-of-defense-implements-section-901-of-the-fy2021-national-defense-aut/|title=Department of Defense Implements Section 901 of the FY2021 National Defense Authorization Act|access-date=2021-01-28}}</ref>}}
|}

==== Notes ====
{{notelist}}

== See also ==
{{columns-list|colwidth=30em|
* [[Base Realignment and Closure Commission]]
* [[Boeing E-4]]
* [[Challenge coin]]
* [[Combat Exclusion Policy]]
* [[Commission to Assess the Ballistic Missile Threat to the United States]]
* [[Continuity of Operations Plan]]
* [[CONPLAN 8022-02]]
* [[Defense Policy Board Advisory Committee]]
* [[Defense Support of Civil authorities]]
* [[Department of Defense Directive 2310]]
* [[Designated survivor]]
* [[Emergency Action Message]]
* [[Global Command and Control System]]
* [[Gold Codes]]
* [[Hamdan v. Rumsfeld]]
* [[Joint Worldwide Intelligence Communications System]]
* [[Key West Agreement]]
* [[McCarran Internal Security Act]]
* [[Military Commissions Act of 2006]]
* [[Military operation plan]]
* [[National Command Authority (United States)]]
* [[National Industrial Security Program]]
* [[National Security Strategy (United States)]]
* [[Office of the Secretary of Defense Identification Badge]]
* [[Packard Commission]]
* [[Permissive Action Link]]
* [[Presidential Successor Support System]]
* [[Quadrennial Defense Review]]
* [[Rules of engagement]]
* [[Secretary of Defense Employer Support Freedom Award]]
* [[Single Integrated Operational Plan]]
* [[State secrets privilege]]
* [[Stop-loss policy]]
* [[Two-man rule]]
* [[Unconventional warfare (United States Department of Defense doctrine)]]
* [[United States Foreign Military Financing]]
* [[US Commission on National Security/21st Century]]
}}

== References ==

=== Citations ===
{{Reflist}}

=== General sources ===
==== Federal law ====
* [[Title 10 of the United States Code]]
* [[Title 50 of the United States Code]]

==== Directives, regulations and manuals ====
* {{Cite book
 |title=Department of Defense Directive 5100.1: Functions of the Department of Defense and Its Major Components
 |publisher=[[U.S. Department of Defense]]
 |location=Washington, D.C.
 |url=http://www.dtic.mil/whs/directives/corres/pdf/510001p.pdf
 |date=December 21, 2010
|ref=5100.1
 |access-date=August 30, 2011
|archive-date=May 25, 2017
|archive-url=https://web.archive.org/web/20170525175933/http://www.dtic.mil/whs/directives/corres/pdf/510001p.pdf
 |url-status=dead
 }}
* {{Cite book
 |title=Department of Defense Manual 1348.33, Volume 1: Manual of Military Decorations and Awards: General Information, Medal of Honor, and Defense/Joint Decorations and Awards
 |publisher=[[U.S. Department of Defense]]
 |location=Washington, D.C.
 |url=http://www.dtic.mil/whs/directives/corres/pdf/134833vol1.pdf
 |archive-url=https://web.archive.org/web/20110322212444/http://www.dtic.mil/whs/directives/corres/pdf/134833vol1.pdf
 |url-status=dead
 |archive-date=March 22, 2011
|date=March 7, 2013 |ref=1348.33, V1}}
* {{Cite book
 |title=Department of Defense Manual 1348.33, Volume 2: Manual of Military Decorations and Awards: General Information, Medal of Honor, and Defense/Joint Decorations and Awards
 |publisher=[[U.S. Department of Defense]]
 |location=Washington, D.C.
 |url=http://www.dtic.mil/whs/directives/corres/pdf/134833vol2.pdf
 |archive-url=https://web.archive.org/web/20110322212453/http://www.dtic.mil/whs/directives/corres/pdf/134833vol2.pdf
 |url-status=dead
 |archive-date=March 22, 2011
|date=May 31, 2013 |ref=1348.33, V2}}
* {{Cite book
 |title=Department of Defense Manual 1348.33, Volume 3: Manual of Military Decorations and Awards: General Information, Medal of Honor, and Defense/Joint Decorations and Awards
 |publisher=[[U.S. Department of Defense]]
 |location=Washington, D.C.
 |url=http://www.dtic.mil/whs/directives/corres/pdf/134833vol3.pdf
 |date=November 23, 2010
|ref=1348.33, V3
 |access-date=June 14, 2013
|archive-date=February 26, 2013
|archive-url=https://web.archive.org/web/20130226205442/http://www.dtic.mil/whs/directives/corres/pdf/134833vol3.pdf
 |url-status=dead
 }}
* {{Cite book
 |title       = Joint Publication 1 – Doctrine for the Armed Forces of the United States
 |publisher   = [[U.S. Department of Defense]]
 |series      = Joint Publications
 |location    = Washington, D.C.
 |url         = http://www.dtic.mil/doctrine/new_pubs/jp1.pdf
 |date        = March 25, 2013
|ref         = JP1
 |url-status     = dead
 |archive-url  = https://web.archive.org/web/20111027024636/http://www.dtic.mil/doctrine/new_pubs/jp1.pdf
 |archive-date = October 27, 2011
}}
* {{Cite book
 |title        = Joint Publication 1-04 – Legal Support to Military Operations
 |publisher    = [[U.S. Department of Defense]]
 |series       = Joint Publications
 |location     = Washington, D.C.
 |url          = http://www.dtic.mil/doctrine/new_pubs/jp1_04.pdf
 |date         = August 17, 2011
|ref          = JP1-04
 |access-date  = June 14, 2013
|archive-url  = https://web.archive.org/web/20130313002939/http://www.dtic.mil/doctrine/new_pubs/jp1_04.pdf
 |archive-date = March 13, 2013
|url-status     = dead
}}

== Further reading ==
* {{Cite book
 |last1=Cohen |first1=Eliot A.
 |author-link=Eliot A. Cohen
 |title=Supreme Command: Soldiers, Statesmen and Leadership in Wartime
 |location=New York
 |publisher=[[Anchor Books]]
 |year= 2003
 |isbn=978-1-4000-3404-8
 |ref=SupCom}}
* {{Cite book
 |editor1-last    = Cole
 |editor1-first   = Alice C.
 |editor2-first   = Alfred
 |editor2-last    = Goldberg
 |editor3-first   = Samuel A.
 |editor3-last    = Tucker
 |editor4-first   = Rudolph A.
 |editor4-last    = Winnacker
 |display-editors = 3
 |title           = The Department of Defense: Documents on Establishment and Organization 1944–1978
 |location        = Washington, D.C.
 |publisher       = Historical Office, [[Office of the Secretary of Defense]]/[[U.S. Government Printing Office]]
 |year            = 1978
 |url             = http://history.defense.gov/resources/DODDocsEstandOrg1944-1978.pdf
 |ref             = DoD1944-1978
 |url-status         = dead
 |archive-url      = https://web.archive.org/web/20140714155622/http://history.defense.gov/resources/DODDocsEstandOrg1944-1978.pdf
 |archive-date     = July 14, 2014
}}
* {{Cite book
 |title       = Department of Defense Key Officials September 1947 – February 2019
 |location    = Washington, D.C.
 |publisher   = Historical Office, [[Office of the Secretary of Defense]]
 |date        = January 30, 2019
|url         = https://history.defense.gov/Portals/70/Documents/key_officials/KeyOfficials2019-01.pdf
 |ref         = DODKO
}}
* {{Cite book
 |last1=Huntington |first1=Samuel P.
 |author-link=Samuel P. Huntington
 |title=[[The Soldier and the State]]
 |location=Cambridge, Massachusetts
 |publisher=The Belknap Press of Harvard University Press
 |year= 1957
 |isbn=0-674-81736-2
 |ref=Huntington}}
* {{Cite book
 |last1=King |first1=Archibald
 |title=Command of the Army
 |series=Military Affairs 
 |location=Charlottesville, Virginia
 |publisher=[[The Judge Advocate General's Legal Center and School|The Judge Advocate General's School, U.S. Army]]
 |orig-year= 1949 |year= 1960
 |url=https://www.loc.gov/rr/frd/Military_Law/pdf/Command-Army_King.pdf |archive-url=https://web.archive.org/web/20080731074337/http://www.loc.gov/rr/frd/Military_Law/pdf/Command-Army_King.pdf |archive-date=2008-07-31 |url-status=live
 |ref=King}}
* Mahan, Erin R., and Jeffrey A. Larsen, eds. (2012). [https://history.defense.gov/Portals/70/Documents/special_studies/SpecStudy3.pdf "Evolution of the Secretary of Defense in the Era of Massive Retaliation: Charles Wilson, Neil McElroy, and Thomas Gates, 1953–1961"], Cold War Foreign Policy Series: Special Study{{spaces}}3 (September 2012), vii–41.
* {{Cite book
 |last1=Stevenson |first1=Charles A.
 |title=SECDEF: The Nearly Impossible Job of Secretary of Defense
 |location=Dulles, Virginia
 |publisher=Potomac Books
 |year= 2006
 |isbn=1-57488-794-7
 |ref=Stevenson}}
* {{Cite book
 |last1       = Trask
 |first1      = Roger R.
 |first2      = Alfred
 |last2       = Goldberg
 |title       = The Department of Defense 1997–1947: Organization and Leaders
 |location    = Washington, D.C.
 |publisher   = Historical Office, [[Office of the Secretary of Defense]]/[[U.S. Government Printing Office]]
 |year        = 1997
 |url         = http://history.defense.gov/resources/DOD1947-1997OrgLeaders.pdf
 |isbn        = 0-16-049163-0
 |ref         = DoD50
 |url-status     = dead
 |archive-url  = https://web.archive.org/web/20140714174451/http://history.defense.gov/resources/DOD1947-1997OrgLeaders.pdf
 |archive-date = July 14, 2014
}}

=== Primary historical sources ===
* {{Cite book
 |last1=Cheney |first1=Dick
 |first2=Liz |last2=Cheney
 |author-link1=Dick Cheney
 |author-link2=Liz Cheney
 |title=[[In My Time: A Personal and Political Memoir]]
 |location=New York
 |publisher=[[Simon & Schuster]]
 |year= 2011
 |isbn=978-1-4391-7619-1
 |ref=Cheney}}
* {{Cite book
 |last1=Rumsfeld |first1=Donald
 |author-link1=Donald Rumsfeld
 |title=[[Known and Unknown: A Memoir]]
 |location=New York
 |publisher=[[Sentinel (publisher)|Sentinel]]
 |year= 2011
 |isbn=978-1-59523-067-6
 |ref=Rumsfeld}}

==== Online sources ====
* {{cite web|url=http://odam.defense.gov/omp/Functions/Organizational_Portfolios/Evolution%20of%205100.1.html|title=Department of Defense Directive 5100.01 Functions of the Department of Defense and Its Major Components|publisher=Office of the Secretary Defense, Director of Administration and Management, Directorate for Organizational & Management Planning|access-date=June 13, 2013|ref=DOMP|url-status=dead|archive-url=https://web.archive.org/web/20130507124537/http://odam.defense.gov/omp/Functions/Organizational_Portfolios/Evolution%20of%205100.1.html|archive-date=May 7, 2013}}

== External links ==
{{commons}}
* {{official website}}

{{s-start}}
{{s-prec|usa}}
{{s-bef|before=[[Scott Bessent]]|as=[[United States Secretary of the Treasury|Secretary of the Treasury]]}}
{{s-ttl|title=[[United States order of precedence|Order of precedence of the United States]]<br>''{{small|as Secretary of Defense}}''|years=}}
{{s-aft|after=[[Pam Bondi]]|as=[[United States Attorney General|Attorney General]]}}
|-
{{s-prec|us-pres}}
{{s-bef|before=[[United States Secretary of the Treasury|Secretary of the Treasury]]<br>{{small|Scott Bessent}}}}
{{s-ttl|title=6th in line}}
{{s-aft|after=[[United States Attorney General|Attorney General]]<br>{{small|Pam Bondi}}}}
{{s-end}}

{{Navboxes
|list =
{{USSecDef}}
{{Current US Department of Defense Secretaries}}
{{DOD agencies navbox}}
{{Defense Intelligence Agency}}
{{US military navbox}}
{{US Cabinet leaders}}
{{US presidential line of succession}}
}}
{{authority control}}

{{DEFAULTSORT:United States Secretary Of Defense}}
[[Category:1947 establishments in the United States]]
[[Category:Lists of members of the Cabinet of the United States|Defense, Secretary of]]
[[Category:Cabinet of the United States|Defense]]
[[Category:United States secretaries of defense| ]]
[[Category:NATO defence ministers]]