The Under Secretary of Defense positions are the six senior civilian jobs that sit directly beneath the Secretary and Deputy Secretary of Defense, each running one of the Pentagon’s main functional areas: Research and Engineering; Acquisition and Sustainment; Policy; Comptroller; Personnel and Readiness; and Intelligence and Security. All six are appointed by the President from civilian life and confirmed by the Senate.
Their place in the department is fixed by statute. 10 U.S.C. § 131 lists the Deputy Secretary first, the Under Secretaries second, and other Senate-confirmed officials and the Chief Information Officer below them.1Office of the Law Revision Counsel. 10 USC 131 – Office of the Secretary of Defense The statute governing Assistant Secretaries confirms the same order, placing them below the Under Secretaries.2Office of the Law Revision Counsel. 10 USC 138 – Assistant Secretaries of Defense Each Under Secretary handles policy, budgets, procurement, and long-range planning inside a delegated portfolio, keeping the business side of the Pentagon under civilian control.
The Six Under Secretaries and What They Do
The order below follows the precedence set by statute.
Research and Engineering
The Under Secretary of Defense for Research and Engineering is the department’s chief technology officer, setting policy on defense research, technology development, prototyping, and developmental testing across the department. The statute requires an extensive background in technology, science, or engineering and experience managing complex programs.3Office of the Law Revision Counsel. 10 USC 133a – Under Secretary of Defense for Research and Engineering This position holds the highest precedence of the six.
Acquisition and Sustainment
The Under Secretary of Defense for Acquisition and Sustainment is the department’s chief acquisition officer, covering system design, production, logistics, maintenance, and materiel readiness. The office also oversees defense industrial base policy and nuclear weapons sustainment and modernization, and its head chairs the Nuclear Weapons Council.4Office of the Law Revision Counsel. 10 USC 133b – Under Secretary of Defense for Acquisition and Sustainment Candidates need extensive experience in system development, engineering, production, or managing complex programs. Ranks second.
Policy
The Under Secretary of Defense for Policy directs and supervises work on the National Defense Strategy, develops planning guidance for combatant commands, shapes global force posture, and produces the Defense Planning Guidance that drives budget requests across the military departments.5Office of the Law Revision Counsel. 10 USC 134 – Under Secretary of Defense for Policy Ranks third.
Comptroller
The Under Secretary of Defense (Comptroller) also serves as the department’s Chief Financial Officer. This official advises the Secretary on all budgetary and fiscal matters, supervises the preparation of budget estimates, and oversees the accounting systems tracking defense spending across every military branch and defense agency.6Office of the Law Revision Counsel. 10 USC 135 – Under Secretary of Defense (Comptroller) Ranks fourth.
Personnel and Readiness
The Under Secretary of Defense for Personnel and Readiness handles military readiness, total force management, recruitment, health affairs, family programs, exchange and commissary operations, and training for both military and civilian personnel.7Office of the Law Revision Counsel. 10 USC 136 – Under Secretary of Defense for Personnel and Readiness Ranks fifth.
Intelligence and Security
The Under Secretary of Defense for Intelligence and Security directs the Military Intelligence Program, executes National Intelligence Program functions delegated by the Secretary, and oversees personnel security, physical security, industrial security, and protection of classified information across the defense enterprise.8Office of the Law Revision Counsel. 10 USC 137 – Under Secretary of Defense for Intelligence and Security Sixth in the precedence order.
Who Can Hold One of These Jobs
Every Under Secretary is appointed from civilian life by the President and confirmed by the Senate. Each enabling statute uses that same phrase, reinforcing that these are civilian posts.3Office of the Law Revision Counsel. 10 USC 133a – Under Secretary of Defense for Research and Engineering Confirmation typically runs through a Senate Armed Services Committee hearing followed by a full Senate vote.
All six positions carry the same restriction on prior military service: no one may be appointed within seven years of leaving active duty as a commissioned officer in a regular military component. That language appears in § 133a, § 133b, § 134, § 135, § 136, and § 137.5Office of the Law Revision Counsel. 10 USC 134 – Under Secretary of Defense for Policy4Office of the Law Revision Counsel. 10 USC 133b – Under Secretary of Defense for Acquisition and Sustainment The seven-year gap keeps recently retired officers from stepping straight into civilian oversight of programs and personnel they were recently connected to.
Pay
All six Under Secretary positions are paid at Level III of the Executive Schedule under 5 U.S.C. § 5314.9Office of the Law Revision Counsel. 5 USC 5314 – Positions at Level III As of January 2026, that annual salary is $209,600.10Office of Personnel Management. Salary Table No. 2026-EX It is the same pay grade as the Under Secretaries of State and Treasury, the Director of the FBI, and the Commissioner of Internal Revenue.
Who Steps In When a Seat Is Vacant
Each Under Secretary is paired with a Deputy Under Secretary, and federal law caps the total at six. The statute is specific: these are the only Deputy Under Secretaries of Defense the department may have.11Office of the Law Revision Counsel. 10 USC 137a – Deputy Under Secretaries of Defense
Each Deputy is designated by statute as the “first assistant” to their Under Secretary and automatically steps into the role if the Under Secretary dies, resigns, or is otherwise unable to serve.12Office of the Law Revision Counsel. 10 US Code 137a – Deputy Under Secretaries of Defense The built-in succession keeps each portfolio staffed during a transition, which matters in a department where gaps in acquisition, intelligence, or nuclear policy leadership carry real consequences.