| Post: | United States Secretary of Defense |
| Insigniasize: | 100px |
| Insigniacaption: | Official Seal |
| Incumbent: | Robert Gates |
| Incumbentsince: | December 18, 2006 |
| First: | James Forrestal |
| Formation: | September 19, 1947 |
| Succession: | Sixth |
| Website: | www.defenselink.mil |
The United States Secretary of Defense (SecDef) is the head of the U.S. Department of Defense (DoD), concerned with the armed services and military matters. This position roughly corresponds to Minister of defense in other countries. The role of the Secretary of Defense is to be the principal defense policy advisor to the President and is responsible for the formulation of general defense policy related to all matters of direct and primary concern to the DoD, and for the execution of approved policy.[1] The Secretary is appointed by the President with the approval of the Senate, and is a member of the Cabinet. By statute () the secretary must be a civilian who has not served in the active component of the armed forces for at least 10 years.[2] The Secretary of Defense is sixth in the presidential line of succession.
The position was created in 1947 when the Navy, Army, and newly created Air Force were merged into the new National Military Establishment. In the same massive reorganization, the Secretary of War was replaced by the Secretary of the Army and, along with the Secretary of the Navy and the new Secretary of the Air Force, became non-Cabinet positions placed under the Secretary of Defense. In 1949, the National Military Establishment was renamed the Department of Defense, which remains the current name of the department.
In the U.S. Armed Forces, the Secretary of Defense is often referred to as "SecDef".
The Secretary of Defense and the President together constitute the National Command Authority (NCA), which has sole authority to launch strategic nuclear weapons. All nuclear weapons are governed by this dual-authority - both must concur before a strategic nuclear strike may be ordered.
The Secretary of Defense heads the United States Office of the Secretary of Defense and is assisted by a Deputy Secretary and five Under Secretaries in the fields of Acquisition, Technology & Logistics; Comptroller/Chief Financial Officer; Intelligence; Personnel & Readiness; and Policy. All of these positions require Senate confirmation.
The Secretary of Defense also supervises the six members of the Joint Chiefs of Staff and the commanders of the ten Unified Combatant Commands.
Along with the Secretary of State, the Attorney General and the Secretary of the Treasury, the Secretary of Defense is generally regarded as one of the "Big Four" important cabinet officials.
| Picture | Name | Term of Office | President(s) served under | ||
|---|---|---|---|---|---|
| Start | End | ||||
| 1 | James Vincent Forrestal | September 19, 1947 | March 19, 1949 | Harry S. Truman | |
| 2 | Louis Arthur Johnson | March 28, 1949 | September 19, 1950 | ||
| 3 | George Catlett Marshall, Jr. | September 19, 1950 | September 19, 1951 | ||
| 4 | Robert Abercrombie Lovett | September 19, 1951 | January 19, 1953 | ||
| 5 | Charles Erwin Wilson | January 19, 1953 | October 19, 1957 | Dwight D. Eisenhower | |
| 6 | Neil Hosler McElroy | October 9, 1957 | December 1, 1959 | ||
| 7 | Thomas Sovereign Gates | December 2, 1959 | January 20, 1961 | ||
| 8 | Robert Strange McNamara | January 21, 1961 | February 29, 1968 | John F. Kennedy, Lyndon B. Johnson | |
| 9 | Clark McAdams Clifford | March 1, 1968 | January 20, 1969 | Lyndon B. Johnson | |
| 10 | Melvin Robert Laird | January 22, 1969 | January 29, 1973 | Richard Nixon | |
| 11 | Elliot Lee Richardson | January 30, 1973 | May 24, 1973 | ||
| 12 | James Rodney Schlesinger | July 2, 1973 | November 19, 1975 | Richard Nixon, Gerald Ford | |
| 13 | Donald Henry Rumsfeld | November 20, 1975 | January 20, 1977 | Gerald Ford | |
| 14 | Harold Brown | January 21, 1977 | January 20, 1981 | Jimmy Carter | |
| 15 | Caspar Willard Weinberger | January 21, 1981 | November 23, 1987 | Ronald Reagan | |
| 16 | Frank Charles Carlucci III | November 23, 1987 | January 20, 1989 | ||
| None | January 20, 1989 | March 20, 1989 | George H. W. Bush | ||
| 17 | Richard Bruce Cheney | March 21, 1989 | January 20, 1993 | ||
| 18 | Leslie Aspin, Jr. | January 21, 1993 | February 3, 1994 | Bill Clinton | |
| 19 | William James Perry | February 3, 1994 | January 24, 1997 | ||
| 20 | William Sebastian Cohen | January 24, 1997 | January 20, 2001 | ||
| 21 | Donald Henry Rumsfeld | January 20, 2001 | December 18, 2006 | George W. Bush | |
| 22 | Robert Michael Gates | December 18, 2006 | Incumbent | George W. Bush, Barack Obama | |
In an Executive Order of December 22, 2005, President George W. Bush modified the line of succession regarding who would act as Secretary of Defense in the event of a vacancy or incapacitation as follows: