Private First Class Robertson was a member of Company I, 3rd Battalion, 180th Infantry Regiment, 45th Infantry Division. He was listed as Missing in Action while fighting the enemy in North Korea on 13 June 1952. He was presumed dead on 31 December 1953. His remains were not recovered. His name is inscribed on the Courts of the Missing at the Honolulu Memorial.

Robertson was awarded the Purple Heart, the Combat Infantryman's 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.