Born in Cuero, Leonard Roy Harmon enlisted in the U. S. Navy in Houston in June 1939. After training in Norfolk, Virginia, he reported for duty on the cruiser "U. S. S. San Francisco" and advanced to mess attendant first class.
During the World War II Battle of Guadalcanal, on November 12, 1942, a Japanese plane crashed into the radar and fire control station of the "San Francisco," causing 50 casualties. The following day, November 13, as the naval battle continued, several officers on the bridge were struck by enemy gunfire. Harmon rushed to help evacuate the wounded to a dressing station. He was killed as he shielded an injured shipmate from gunfire. For this act of extraordinary heroism, he was awarded the Navy Cross.
On May 21, 1943, Frank Knox, secretary of the Navy, announced the naming of a Navy vessel in Harmon's honor. The first U. S. warship named for a black man, the destroyer escort "U. S. S. Harmon" was christened by Mrs. Naunita Harmon Carroll, Harmon's mother, and launched on July 25, 1943. The vessel received three battle stars for service in the Pacific during World War II. In 1975, as a further memorial, the bachelor enlisted quarters at the U. S. Naval Air Station, North Island, California, was named Harmon Hall.