Henry Follin Agnew was born in Frederickstown, Ohio, on 6 December 1898, son of Mrs. Emma Follin Agnew and the late Murray J. Agnew. He attended high schools in Frederickstown, Ohio, and Visalia, California, before entering the US Naval Academy, Annapolis, Maryland, from California at large, on 20 June 1918. As a Midshipman he was a member of his Class Saber Team. Graduated and commissioned Ensign on 8 June 1923, he subsequently advanced to the rank of Captain, to date from 10 November 1945.
After graduation from the Naval Academy in June 1923, he had more than four years' service in destroyers of the Pacific Fleet, based at San Diego, California, assigned first to USS Farquhar, and later in turn to USS Stoddert and USS Moody. He attended the Submarine School, New London, Connecticut, January-June 1928, and upon completion of the course was ordered to Asiatic Station, where he had consecutive duty in the Submarines S-40, S-39, and S-38. He returned to the Naval Academy in the summer of 1931, to serve for two years as an instructor in the Department of Electrical Engineering and Physics.
Duty as Division Watch Officer of USS Texas from 1933 until 1936, during which period his division won the Efficiency "E" in short range battle practice, was followed by a two year tour of duty as Regimental Commander, South Unit, US Naval Training Station, San Diego, California. For four years thereafter he was at sea, first as First Lieutenant of USS Cincinnati, and in 1941-1942 as Navigator of USS Chester. While he was in the latter assignment, the United States entered World War II, and the Chester participated in the escort of several convoys, including that of the Queen Elizabeth from San Francisco to Australia, and engaged in the first Marshall raid and the Battle of the Coral Sea.
He again had duty during 1943-1944, at the Naval Academy as Executive Officer in the Department of Ordnance and Gunnery. In that assignment he supervised the modernization of the entire training equipment of the Ordnance Department and the curriculum. The next two years he served as an LST Commander in the Amphibious Forces, Pacific Fleet, and assisted in the training of many hundreds of officers and men. As Convoy Commander he participated in the original occupational landings in Southern Kyushu; the servicing of landing forces along the shores of Kyushu from Fukuoka to Nagasaki and Hagoshima; and the stripping of 100 LST's at Yokahama for use of the Japanese in repatriation operations.
Returning to the United States in February 1946, he was assigned as Civilian Personnel Director, Eleventh Naval District, San Diego, California, serving once on General Court Martial duty; on many occasions as the Commandant's Representative in civic organizations; and on public speaking tours throughout the District. In addition, he served as the President of the Federal Business Association from June 1947 to June 1948. On 12 May 1949 he was ordered detached and to duty as Commanding Officer of USS Oglethorpe (AKA 100).
Captain Agnew had the Victory Medal (World War I); the American Defense Service Medal, Fleet Clasp; American Campaign Medal; AsiaticPacific Campaign Medal with two engagement stars and the World War II Victory Medal. He also held the Expert Rifleman's Medal.
He was a member of the San Diego Personnel Association, and had been President of the Federal Business Association of San Diego.