United States Department of the Navy The United States Department of the Navy ( DON ) was established by an Act of Congress on 30 April 1798 ( initiated by the recommendation of James McHenry ) , to provide a government organizational structure to the United States Navy and , from 1834 onwards , for the United States Marine Corps , and when directed by the President , for the United States Coast Guard as a service within the Navy . The Department of the Navy was an Executive Department and the Secretary of the Navy was a member of the President ' s cabinet until 1949 , when amendments to the National Security Act of 1947 changed the name of the " National Military Establishment " to the " Department of Defense " and made it an Executive Department . The Department of the Navy then became , along with the Department of the Army and Department of the Air Force , a " Military Department " within the Department of Defense : subject to the authority , direction and control of the Secretary of Defense . Leadership . The Department of the Navy is headed by the Secretary of the Navy , also known as the " SECNAV " in naval jargon , who has the authority to conduct all of the affairs of the Department : subject to lawful authority , the Secretary of Defense , and the President . The Secretary of the Navy is appointed by the President with the advice and consent of the Senate . The Secretary is assisted by an Under Secretary of the Navy , four Assistant Secretaries of the Navy and a General Counsel of the Department of the Navy , who are also appointed by the President with the advice and consent of the Senate . The highest ranking military officer s in the Department of the Navy are the Chief of Naval Operations and the Commandant of the Marine Corps , who are the principal military advisors to the Secretary of the Navy . They supervise their respective military services of the Department of the Navy , and in a separate capacity serves as members of the Joint Chiefs of Staff . They are assisted by a Vice Chief of Naval Operations and an Assistant Commandant of the Marine Corps . Composition . Unlike its Army and Air Force counterparts , the Department of the Navy comprises two uniformed services : the United States Navy and the United States Marine Corps ( sometimes collectively called the " naval services " or " sea services " ) . The Department of the Navy consists of all elements of the United States Navy and the United States Marine Corps . According to Navy Regulations Section 0204 - 2 , the term " Navy Department " refers only to the executive offices at the seat of government . The Department of the Navy is composed of the following : Proposed redesignation . A provision in the initial House of Representatives bill ( H . R . 1585 ) for the fiscal year 2008 national defense authorization would have renamed the Department of the Navy as the " Department of the Navy and Marine Corps . " The bill passed in the House on 17 May 2007 , but encountered opposition among members of the DoD civilian leadership and among senior Navy admirals and Marine Corps generals . In the Senate , the provision was replaced in S . Amdt . 2011 , an amendment in the nature of a substitute proposed by Senator Carl Levin of Michigan on 9 July 2007 and agreed to by unanimous consent on 1 October 2007 . The amendment removed the renaming provision and also made other changes . The House version including the provision was withdrawn in conference committee and so was not included in the final National Defense Authorization Act for Fiscal Year 2008 .