Born in Sioux City, Iowa, and raised in the midwestern states of Nebraska, Missouri and Illinois, Admiral Clark graduated from Evangel College and earned a Master's Degree of Business Administration (MBA) from the University of Arkansas. He attended Officer Candidate School and received his commission in August 1968.
Admiral Clark served aboard the destroyers USS John W. Weeks (DD 701) and USS Gearing (DD 710). As a lieutenant, he commanded USS Grand Rapids (PG 98). He subsequently commanded USS McCloy (FF 1038), USS Spruance (DD 963), the Atlantic Fleet's Anti-Submarine Warfare Training Center, Destroyer Squadron Seventeen, and Destroyer Squadron Five.
After being selected for flag rank, Admiral Clark commanded the Carl Vinson Battle Group/Cruiser Destroyer Group Three, the Second Fleet, and the United States Atlantic Fleet.
Ashore, Admiral 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, Naval Surface Force, U.S. Atlantic Fleet, and he directed the Joint Staff's Crisis Action Team for Desert Shield and Desert Storm.
Admiral Clark's first flag assignment was at the U.S. Transportation Command where he was Director of both Plans and Policy (J5) and Financial Management and Analysis (J8).
While commanding the Carl Vinson Battle Group, he deployed to the Arabian Gulf and later served as the Deputy Commander, Joint Task Force Southwest Asia. Admiral 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.
Admiral Clark became the 27th Chief of Naval Operations on July 21, 2000.
Admiral Clark's personal decorations include the Defense Distinguished Service Medal (three awards), the Distinguished Service Medal (two awards), the Legion of Merit (three awards), the Defense Meritorious Service Medal, the Meritorious Service Medal (four awards), the Navy Commendation Medal, and various service and campaign awards.