The commandant of the Marine Corps (CMC) is normally the highest-ranking officer in the United States Marine Corps. It is a four-star general position and a member of the Joint Chiefs of Staff. The CMC reports directly to the secretary of the Navy and is responsible for ensuring the organization, policy, plans, and programs for the Marine Corps as well as advising the president, the secretary of defense, the National Security Council, the Homeland Security Council, and the secretary of the Navy on matters involving the Marine Corps. Under the authority of the secretary of the Navy, the CMC designates Marine personnel and resources to the commanders of unified combatant commands. The commandant performs all other functions prescribed in Section 8043 in Title 10 of the United States Code or delegates those duties and responsibilities to other officers in his administration in his name. As with the other joint chiefs, the commandant is an administrative position and has no operational command authority over United States Marine Corps forces.

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.