person who is enlisted in a branch of the armed force
United States Armed Forces oath of enlistment Upon enlisting in the United States Armed Forces, each person enlisting in an armed force (whether a soldier, sailor, coast guardsman, airman, or Marine) takes an oath of enlistment required by federal statute in 10 U.S.C. § 502. That section provides the text of the oath and sets out who may administer the oath:
Chairman of the Joint Chiefs of Staff The Chairman of the Joint Chiefs of Staff (CJCS) is, by U.S. law, the highest-ranking and senior-most military officer in the United States Armed Forces[2] and is the principal military advisor to the President, the National Security Council,[3] the Homeland Security Council,[3] and the Secretary of Defense.[3][4] While the Chairman of the Joint Chiefs of Staff outranks all other commissioned officers, he is prohibited by law from having operational command authority over the armed forces; however, the Chairman does assist the President and the Secretary of Defense in exercising their command functions.[2]