Corporal Gaddis was a member of the 21st Infantry Regiment, 24th Infantry Division. He was seriously wounded by the enemy in South Korea on 2 September 1950 and returned to duty on 27 September 1950. He was Killed in Action while fighting the enemy in South Korea on 28 May 1951.

Gaddis was awarded the Purple Heart with Oak Leaf Cluster, the Combat Infantryman Badge, 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.