Captain Larkin was the pilot of a F-84E Thunderjet fighter with Headquarters Squadron, 136th Fighter Bomber Wing. On 5 December 1951, while on a combat mission, his aircraft and another F-84 were attacked by two MiGs. He ejected and his plane crashed into the water. He was listed as Missing in Action and was presumed dead on 28 February 1954. His remains were not recovered. His name is inscribed on the Courts of the Missing at the Honolulu Memorial.

Larkin was awarded the Air Medal, 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.