Secretary of Defense

The National Security Act of 1947 created the post, and James Forrestal, the last Secretary of the Navy to sit in the cabinet, became the first Secretary of Defense. The 1949 amendments strengthened the office into the head of a single executive department. The Secretary is nominated by the President, confirmed by the Senate after hearings before the Armed Services Committee, and is sixth in the line of presidential succession.

The Secretary exercises authority, direction, and control over the entire Department of Defense. The operational chain of command runs from the President through the Secretary directly to the combatant commanders, bypassing the service chiefs, and the Secretary shares with the President the authority to order military operations. The Secretary sets the defense budget request, decides major weapons programs, and approves the promotion and assignment of senior officers.

Civilian control of the military is written into the qualifications: by law a Secretary must have been out of active-duty service for at least seven years, originally ten. Congress has waived the rule three times, for George Marshall in 1950, James Mattis in 2017, and Lloyd Austin in 2021, each over objections that waivers erode the principle. In 2025 the President authorized the title Secretary of War as a secondary designation by executive order, though the statutory title remains Secretary of Defense unless Congress changes it.