In 1919 he was promoted to Admiral and commanded the Asiatic Fleet. While serving at the Naval Ordnance Proving Ground, Admiral Gleaves made outstanding contributions in the field of gunnery and torpedoes. While carrying out some tests on torpedo steering devices he changed these weapons from instruments of luck into instruments of precision. The gear which he tested in Gushing provided the imprints which made the torpedo the "terrible weapon" of World War I.
In spite of a life of constant action in war and peace, he found time to write a biography of Captain James Lawrence; the History of the Cruiser and Transport Force, and the Life of an American Sailor, William Hensley Emory, Rear Admiral, USN. After a most distinguished career, he retired in 1921.
Admiral Gleaves died at Haverford, Pennsylvania, a few days after his 79th birthday.
He has been quoted as saying, "To seamen a ship becomes endowed with human virtues and faults; she ceases to be a mere inanimate thing."