in 2005. Clark served aboard the destroyers and . As a lieutenant, he commanded . He subsequently commanded , , the Atlantic Fleet's Anti-Submarine Warfare Training Center, Destroyer Squadron 17, and Destroyer Squadron 5. After being selected for flag rank, Clark commanded
Carl Vinson Battle Group/
Cruiser-Destroyer Group 3,
Second Fleet, and
United States Atlantic Fleet. Ashore, Clark first served as special assistant to the director of the Systems Analysis Division in the Office of the Chief of Naval Operations. He later completed assignments as the administrative assistant to the Deputy Chief of Naval Operations (Surface Warfare) and as the administrative aide to the
Vice Chief of Naval Operations. He served as head of the Cruiser-Destroyer Combat Systems Requirements Section and force anti-submarine warfare officer for the commander of Naval Surface Force, Atlantic Fleet, and he directed the Joint Staff's Crisis Action Team for
Operation Desert Shield and
Operation Desert Storm. Clark's first flag assignment was at the
United States Transportation Command (TRANSCOM), where he was director of plans and policy (J5) and financial management and analysis (J8). While commanding the
Carl Vinson Battle Group, he deployed to the
Persian Gulf and later served as the Deputy Commander, Joint Task Force Southwest Asia. Clark has also served as the Deputy and Chief of Staff, United States Atlantic Fleet; the Director of Operations (J3) and subsequently
Director, of the Joint Staff. Clark became the 27th
Chief of Naval Operations on July 21, 2000, relieving
Jay L. Johnson. Since his retirement, Clark has been honored with the Eisenhower Award from the Business Executives for National Security and the
Distinguished Sea Service Award from the
Naval Order of the United States. Clark was elected to the board of directors of
Raytheon in December 2005 and the board of directors of
SRI International in March 2007. Clark now serves on the board of directors of Raytheon Company, Rolls-Royce North America, SRI International, Horizon Lines, the Armed Forces YMCA, and is on the world board of governors of the USO. He serves as a senior advisor with
Booz Allen Hamilton, the Defense Policy Board, the advisory boards of Fleishman-Hillard, Computer Science Corporation, the Comptroller General's advisory board of the GAO, and the executive committee of Military Ministry. In addition, he is currently a distinguished professor at
Regent University in
Virginia Beach,
Virginia. Clark teaches in the Robertson School of Government and the School of Business & Leadership and is a member of the Regent's board of trustees. He was also a member of the Board of Visitors at
Air University. ==Awards and decorations==