After training as an aviation cadet at Naval Air Station Pensacola, Florida, he was commissioned Ensign on 7 July 1939 and began flying duty with a torpedo plane squadron.

Leading his squadron in an unsupported aerial torpedo raid against an Imperial Japanese Navy (IJN) task force, Lieutenant Harwood pressed home the attack through antiaircraft fire.

Leading an attack group of bombers through adverse flying conditions, he located a force of IJN destroyers landing troops and supplies on Guadalcanal.

The following night he and his bombers flying on instruments through a violent tropical storm to Rekata Bay, bombed shore installations there despite fierce opposition from Japanese fighter planes which swarmed to the attack.

Redesignated DDE-861 on 4 March 1950, the escort destroyer reported to her new home port, Naval Station Newport, Rhode Island, on 11 September 1949 to participate in research on cold weather ASW operations as well as fleet and training exercises.

Harwood sailed 4 January 1957 for a 3-month ASW demonstration which took her along the South American coast to Colombia, Ecuador, Peru, Chile, Panama and Cuba.

Her bridge was totally reconstructed, new types of torpedo tubes were installed, and the 76 mm antiaircraft guns were removed to accommodate a hangar and launching deck for Gyrodyne QH-50 DASH anti-submarine drones.

When the Cuban Missile Crisis erupted in October 1962, Harwood and sailed with 4 hours' notice to join the blockading fleet "quarantining" Cuba.

Reaching Naval Station Rota, Spain on 10 July, Harwood soon joined the 6th Fleet, an element of stability in the ancient and volatile sea which had so recently been churned by the Six-Day War.