Corporal Cooper was a member of Battery A, 15th Field Artillery Battalion, 2nd Infantry Division. He was listed as Missing in Action while fighting the enemy near Hoengsong, South Korea on 13 February 1951. He was presumed dead on 3 March 1954. His name is inscribed on the Courts of the Missing at the Honolulu Memorial.

Cooper 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.