Born in Hampton, Iowa, 6 May 1875, William Daniel Leahy entered the Naval Academy in 1893 from Wisconsin. He was commissioned ensign 1 July 1899 and through subsequent promotions attained the rank of rear admiral in October 1927; vice admiral July 1935; admiral January 1937; and fleet admiral December 1944.
He sailed in CONSTELLATION on a midshipman's cruise. Upon graduation he, served on OREGON, a key part of the powerful "new Navy" of that era during the destruction of the Spanish fleet in Santiago 3 July 1898. In October he joined TEXAS, and in 1899 proceeded to the Asiatic Station where he saw active service during the Philippine Insurrection and Boxer Rebellion in China. He returned to the United States in 1904, and in June was on board BOSTON stationed at Panama during early construction of the Canal. After instructing at the Naval Academy, then serving as navigator of CALIFORNIA, in 1912 he commanded American naval forces during the occupation of Nicaragua.
In September 1915 he assumed command of gunboat DOLPHIN operating in the West Indies searching for German supply ships, became executive officer of NEVADA July 1917, and in 1918 won the Navy Cross as commander of PRINCESS MATOIKA transporting troops to France.
In April 1921 he commanded ST. LOUIS, flagship of the naval detachment protecting American interests during the Greco-Turkish War. After command of NEW MEXICO in 1926, he returned to the Navy Department as Chief of the Bureau of Ordnance October 1927. In June 1931 Admiral Leahy became Commander, Destroyers, U.S. Fleet, and May 1933 was appointed to the board then reorganizing the Navy Department.
In 1936 he became Commander in Chief, Battle Force, and broke his flag in CALIFORNIA. Appointed Chief of Naval Operations, he took the oath 2 January 1937 and held that office until he retired 1 August 1939. Several days prior to his retirement the President presented him with the Distinguished Service Medal.
He became Governor of Puerto Rico 11 September 1939, and Ambassador to France 23 November 1940 in the critical early years of World War 11. On 20 July 1942 he was returned to active duty as Chief of Staff to President Roosevelt, and for a time was senior member of the Joint Chiefs of Staff. On 15 December 1944, he was appointed Fleet Admiral (with only three other admirals to receive the distinction of a fifth star: King, Nimitz, and Halsey). He remained on active duty in an advisory capacity in the Office of the Secretary of the Navy until his death 20 July 1959.
Ships named after Fleet Admiral William Daniel Leahy: