An Act to promote the national security by providing for a Secretary of Defense; for a National Military Establishment; for a Department of the Army, a Department of the Navy, a Department of the Air Force; and for the coordination of the activities of the National Military Establishment with other departments and agencies of the Government concerned with the national security.
The National Security Act of 1947 was a major restructuring of the United States government's military and intelligence agencies following World War II. The majority of the provisions of the Act took effect on September 18, 1947, the day after the Senate confirmed James Forrestal as the first Secretary of Defense. His power was initially limited and it was difficult for him to exercise the authority to make his office effective. This was later changed in the amendment to the act in 1949, creating what was to be the Department of Defense.
The Joint Chiefs of Staff was officially established under Title II, Section 211 of the original National Security Act of 1947 before Sections 209–214 of Title II were repealed by the law enacting Title 10 and Title 32, United States Code (Act of August 10, 1956, 70A Stat. 676) to replace them.