Secretary of Defense

Updated: February 11, 2021
In this Article

    What is the Secretary of Defense and what does this job require?

    Title 10 of the United States Code provides both the legal basis for the existence of the Department of Defense, but also for the existence of the service chiefs and the Secretary of Defense, a cabinet-level position sometimes referred to as SecDef for short.

    Under Title 10, the person holding the office of Secretary of Defense serves as the chief of the DoD, acting as “the principal assistant to the President in all matters,” related to DoD and essentially maintains “authority, direction and control over the Department of Defense.”

    The job of the Office Of The Secretary of Defense (OSD) includes developing and evaluating policy, establishing and maintaining training and planning operations, resource management, and related duties. This is a vast oversimplification of the job as it involves a number of far-reaching issues and variables including military budgets, troop strength, current threat levels and mission requirements worldwide, etc.

    According to the Department of Defense, the OSD mission includes “the offices of top civilian defense decision-makers with regard to personnel, weapons acquisition, research, intelligence and fiscal policy,” and also includes the offices established by SECDEF to carry out the assignments of the Secretary.

    Due to the Constitutionally-dictated requirement to maintain civilian control of the United States military with a purpose that includes preventing the military from being used to enforce U.S. laws on U.S. soil, the office of the Secretary of Defense must be held by a civilian.

    In cases where a former military member is under consideration for the post, the appointee must be retired from military service for at least seven years. That requirement was originally set at 10 years, and there have been waivers of the seven-year rule in cases up to and including the 2021 appointment for the position.

    Some sources report only three such waivers being granted over the entire lifetime of the office. Army General George Marshall, Marine Corps General Jim Mattis, and Army General Lloyd Austin III.

    A Brief History Of The Secretary Of Defense

    Before Title 10 of the United States Code, the National Security Act of 1947 was the legislative means of establishing OSD and a Secretary of Defense.

    Prior to this, and dating all the way back to the 1700s, the President of the United States was tasked with providing direction and control to the nation’s armed forces. But the office of the President would grow to the extent that the Commander-in-Chief could no longer be personally responsible for these duties.

    Historians note that by the time the United States began making itself known as a global power, the Commander-in-Chief found himself relying on subordinates to handle some or all of these duties. Some historians believe by the time World War Two got underway, this position was basically untenable or in danger of becoming so; in 1947 Congress took steps to remedy the situation.

    Enter the National Security Act of 1947 and an against-tradition move to continue to keep command and control of the nation’s military under civilian control without merging the separate services.

    Some history books written specifically about the Secretary of Defense hold that the National Security Act of 1947 went far beyond a simple reorganization of responsibilities and organization; it created a formal structure to create national security policy at the cabinet level.

    The Act gave the sitting president a “full-time deputy for military affairs” and simultaneously made the military service secretaries (Secretary of the Army, Secretary of the Navy, etc.) subordinate to the OSD.

    OSD began in September 1947; the first Secretary of Defense was James Vincent Forrestal who served from 17 September 1947 to 28 March 1949. He was replaced by Louis Arthur Johnson, who served until September 1950.


    The Duties Of The Secretary Of Defense

    A DoD-level publication title JP1-0, Joint Personnel Support, published in 2020 at the direction of the Chairman of the Joint Chiefs of Staff, includes this description of the role of the Secretary of Defense, states, “SecDef establishes policy, assigns responsibilities, and prescribes procedures for personnel readiness issues for the Active Component (AC), Reserve Component (RC), DOD civilians, and contractors.”

    Title 10 of the United States Code contains, among many other things, a list of the Title 10-dictated duties of SECDEF, who is required to “develop and maintain” a “supply catalog” as well as standardization programs dictated in Section 2451 of Title 10.

    That duty requires maintenance of a “single catalog system and related program of standardizing supplies for the Department of Defense.” What kind of standardization?

    According to Title 10, “In cataloging, the Secretary shall name, describe, classify, and number each item recurrently used, bought, stocked, or distributed by the Department of Defense, so that only one distinctive combination of letters or numerals, or both, identifies the same item throughout the Department of Defense.”

    That may sound like a deep-level detail of a very big job, why do we mention it here and up front? Believe it or not, that job alone is so large that it is actually the FIRST DUTY listed in Title 10. It’s closely associated with military readiness and as such is definitely appropriate to be listed as a responsibility for the office.

    What are the other duties? Among many other things, “establish, publish, review, and revise, within the Department of Defense, military specifications, standards, and lists of qualified products, and resolve differences between the military departments, bureaus, and services with respect to them”.

    Another requirement of SECDEF is to “maintain liaison with industry advisory groups” to maintain a high level of standardization,

    Current SECDEF And Former Secretaries Of Defense

    • Lloyd J. Austin III – Biden Administration
    • Mark T. Esper – Trump Administration
    • James N. Mattis – Trump Administration
    • Ashton B. Carter – Obama Administration
    • Chuck Hagel – Obama Administration
    • Leon E. Panetta – Obama Administration
    • Robert M. Gates – George W. Bush / Obama Administration
    • Donald H. Rumsfeld – George W. Bush Administration
    • William S. Cohen – Clinton Administration
    • William J. Perry – Clinton Administration
    • Leslie Aspin – Clinton Administration
    • Richard B. Cheney – George H.W. Bush Administration
    • Frank C. Carlucci – Reagan Administration
    • Caspar W. Weinberger – Reagan Administration
    • Harold Brown – Carter Administration
    • Donald H. Rumsfeld – Ford Administration
    • James R. Schlesinger – Nixon / Ford Administration
    • Elliot L. Richardson – Nixon Administration
    • Melvin R. Laird – Nixon Administration
    • Clark M. Clifford – Johnson Administration
    • Robert S. McNamara – Kennedy / Lyndon Johnson Administration
    • Thomas S. Gates, Jr. – Eisenhower Administration
    • Neil H. McElroy – Eisenhower Administration
    • Charles E. Wilson – Eisenhower Administration
    • Robert A. Lovett – Truman Administration
    • George C. Marshall -Truman Administration
    • Louis A. Johnson – Truman Administration
    • James V. Forrestal – Truman Administration

    About The AuthorJoe Wallace is a 13-year veteran of the United States Air Force and a former reporter for Air Force Television News

    Written by Team