First Lieutenant McNulty was the pilot of a F-80C Shooting Star fighter interceptor with the 80th Fighter Bomber Squadron, 8th Fighter Bomber Group. During an air strike from Suwon Air Base against Yangdok, North Korea on 16 January 1952, contact was lost and he was listed as Missing in Action. He was presumed dead on 31 December 1953. His remains were not recovered. His name is inscribed on the Courts of the Missing at the Honolulu Memorial.

McNulty was awarded the Air Medal with Oak Leaf Cluster, the Purple Heart, the Korean Service Medal, the United Nations Service Medal, the National Defense Service Medal, the Korean Presidential Unit Citation and the Republic of Korea War Service Medal.