Corporal Dillion was a member of Company B, 3rd Engineer Combat Battalion 24th Infantry Division. He was listed as Missing in Action while fighting the enemy in South Korea on 11 August 1950. He was presumed dead on 31 December 1953. His name is inscribed on the Courts of the Missing at the Honolulu Memorial.

Dillion was awarded 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.