Ships
- USS Aaron Ward (DD-483) Captain, 4 March 1942 – 18 February 1943
- USS Walker (DD-517) Captain from 3 April 1943
Orville Francis Gregor was born in Missouri on 1 April 1903. He graduated from the United States Naval Academy with the class of 1924 and made his career in the United States Navy. He retired as a rear admiral and died in Montgomery, Alabama, on 24 February 1978.
On 4 March 1942 Gregor became commanding officer of the new Gleaves-class destroyer Aaron Ward (DD-483), the day the ship was commissioned. He was then a lieutenant commander. Aaron Ward tried herself out from Casco Bay, Maine, spent time in the New York Navy Yard, and on 20 May 1942 headed for the Pacific by way of the Panama Canal. In July 1942 he was given the temporary rank of commander.
That June, while the Battle of Midway was being fought farther west, Aaron Ward screened a battleship force under Vice Admiral William S. Pye, Task Force 1, which also included the escort carrier Long Island. The group reached a station on the order of 1,200 miles west of San Francisco. When Long Island left the force on 17 June, Aaron Ward escorted her back to San Diego. At the end of June Gregor took the destroyer to Hawaii, and from there she sailed for the Tonga Islands with Task Force 18.
In the South Pacific, Aaron Ward joined the ships covering and supplying Guadalcanal. On 15 September 1942 she was in company when the Japanese submarine I-19 torpedoed the carrier Wasp. Through October and November the destroyer also shelled Japanese positions ashore in support of the Marines. Lieutenant Commander Frederick Julian Becton served as her executive officer.
On the night of 12–13 November 1942, near Savo Island, Gregor took Aaron Ward into the Naval Battle of Guadalcanal. The American force he was with closed to short range, inflicted heavy damage on a stronger Japanese formation, and kept that force from carrying out its attack on the island. Aaron Ward was struck repeatedly. The hits killed and wounded men and left her badly crippled, for a time unable to pull away from the guns of a Japanese battleship. Her engineers made temporary repairs, got her underway, and brought her out. Admiral William F. Halsey afterward praised the crew for saving the ship. Gregor received the Navy Cross for his leadership that night.
He remained commanding officer of Aaron Ward while she was repaired and gave up the ship on 18 February 1943. On 3 April 1943 he took command of the Fletcher-class destroyer Walker (DD-517) and stayed in her until 27 July 1943. On 10 June 1943, during that command, he was advanced to the temporary rank of captain.
In January 1944 Gregor commanded a task group in the preparations for the landings at Anzio and Nettuno, on the Italian coast, and during the landings themselves. He was awarded the Legion of Merit for that service. He retired in 1947 as a rear admiral.