Donald Bradley Duncan was born in Alpena, Michigan, in 1896, graduated from the U.S. Naval Academy in 1917 and served on the battleship OKLAHOMA until 1920, when he began naval flight training. He served in several observation squadrons in the 1920s and also earned a Master of Science degree in radio engineering. During the 1930s he was detailed in Washington, D.C., in the Navy Bureau of Aeronautics as well as in aircraft scouting squadrons and on staffs at sea. In 1941 he managed the first merchant ship-to-aircraft carrier conversion and then commanded USS LONG ISLAND (CVE-1). During his staff duty early in WWII he played a leading part in planning the Doolittle Tokyo raid of 18 April 1942, culminating in his message to General Hap Arnold, "Tell Jimmy to get on his horse," which sent Doolittle and his group to California to meet the aircraft carrier HORNET.
Duncan took command of the new aircraft carrier ESSEX in December 1942, participating in significant action in the Pacific War. Staff duty at successively higher levels led to promotion to Rear Admiral, command of carrier divisions, Vice Admiral and command of the Second Fleet in the Atlantic in 1948. He became Deputy Chief of Naval Operations in 1950 and in 1951 Vice Chief of Naval Operations with the rank of Admiral. Admiral Duncan retired from active duty in 1957 after a 40-year career.