The Joint Chiefs of Staff (JCS) is the body of the most senior uniformed leaders within the United States Department of Defense, which advises the president of the United States, the secretary of defense, the Homeland Security Council and the National Security Council on military matters. The composition of the Joint Chiefs of Staff is defined by statute and consists of a chairman (CJCS), a vice chairman (VJCS), the chiefs of the Army, Marine Corps, Navy, Air Force, Space Force, and the chief of the National Guard Bureau. Each of the individual service chiefs, outside their JCS obligations, works directly under the secretaries of their respective military departments, e.g. the secretary of the Army, the secretary of the Navy, and the secretary of the Air Force.
The Joint Chiefs of Staff in March 2022.
United States Secretary of Defense Harold Brown and United States Deputy Secretary of Defense Charles W. Duncan Jr with Chairman of the Joint Chiefs of Staff General George S. Brown and the other members of the Joint Chiefs of Staff at the Pentagon in 1977
Joint Chiefs of Staff meeting (circa 1943). From left to right are: Gen. Henry H. Arnold, Chief of the Army Air Forces; Adm. William D. Leahy, Chief of Staff to the Commander in Chief of the Army and Navy; Adm. Ernest J. King, Commander in Chief, U.S. Fleet and Chief of Naval Operations; and Gen. George C. Marshall, Chief of Staff of the United States Army.
The Joint Chiefs of Staff in 1959. From left to right: Gen. Lyman L. Lemnitzer, USA; Adm. Arleigh A. Burke, USN; Gen. Nathan F. Twining, USAF (chairman); Gen. Thomas Dresser White, USAF; and Gen. Randolph M. Pate, USMC
United States Department of Defense
The United States Department of Defense is an executive branch department of the federal government of the United States charged with coordinating and supervising all agencies and functions of the U.S. government directly related to national security and the United States Armed Forces. As of June 2022, the U.S. Department of Defense is the largest employer in the world, with over 1.34 million active-duty service members, including soldiers, marines, sailors, airmen, and guardians. The Department of Defense also maintains over 778,000 National Guard and reservists, and over 747,000 civilians bringing the total to over 2.87 million employees. Headquartered at the Pentagon in Arlington County, Virginia, just outside Washington, D.C., the Department of Defense's stated mission is to provide "the military forces needed to deter war and ensure our nation's security".
President Truman signs the National Security Act Amendment of 1949
A December 2013 Department of Defense organizational chart
Joint Chiefs of Staff and Joint Staff organizational chart