Corporal Theodorou was a member of Company C, 1st Battalion, 32nd Infantry Regiment, 7th Infantry Division. He was listed as Missing in Action while fighting the enemy along the "Kansas Line" near Inje, North Korea on April 26, 1951. He was presumed dead on December 31, 1953. His remains were not recovered. His name is inscribed on the Courts of the Missing at the Honolulu Memorial.