Organizational Policy and Decision Support (OP&DS) White Paper: Evolution of Department of Defense Directive (DoDD) 5100.01, "Functions of the Department of Defense and Its Major Components"



This White Paper captures the history of legislative and Department of Defense (DoD) directed reforms and resultant changes in the roles and missions of the major DoD Components, as codified in the evolving versions of the DoDD 5100.01 to the present. Within the Office of the Secretary Defense, the Office of the Chief Management Officer of the Department of Defense (OCMO), the Directorate of Administration, OP&DS Office is responsible for maintaining and updating DoDD 5100.01, "Functions of the Department of Defense and Its Major Components." The Directive describes the organizational relationships within the Department, and is the foundational issuance for delineating the major functions of the Department. The latest version, Change 1 to the December 2010 version signed by then-Secretary Gates, was finalized on September 17, 2020 and addressed primarily "fact of life" organizational changes that have occurred since 2010.


Most Recent Update to DoDD 510001:

The Administrative Change 1 to DoDD 5100.01, September 17, 2020, primarily reflected changes in law and major DoD policy decisions, and updated select references and title changes, to include:

  1. Addition of the Chief of the National Guard Bureau to membership of the Joint Chiefs of Staff.

  2. The reorganization of the OCMO; the restructuring of the Offices of the Under Secretary of Defense (OUSD) for Acquisition, Technology, and Logistics into the OUSD for Research and Engineering and the OUSD for Acquisition and Sustainment.

  3. The establishment of U.S. Cyber Command, U.S. Space Force, Principal Cyber Advisor, Defense Health Agency, Defense POW/MIA Accounting Agency, and Space Development Agency; retitling of the Defense Security Service as the Defense Counterintelligence and Security Agency; and disestablishment of the Defense Business Transformation Agency.


White Paper Abstract:

The White Paper, "Evolution of Department of Defense Directive 5100.01, Functions of the Department of Defense and Its Major Components," examines the evolution of the DoDD 5100.01, "Functions of the Department of Defense and Its Major Components." It reviews the post-World War II defense reform debates that resulted in issuance of the first DoDD 5100.01, highlights key modifications made to the Directive over time, and identifies the stakeholders behind each revision. Because U.S. military roles and missions naturally feed into, and often dictate, the functions described in the Directive, this paper also includes a discussion of roles and missions as they have changed over time. This White Paper can serve as a valuable reference regarding the history of the DoD, the evolution of its roles and missions, and related policy discussions.