Corporal McClellan was a member of Company E, 2nd Battalion, 7th Marines, 1st Marine Division. He participated in the landing at Inchon. He was Killed in Action while fighting the enemy at the Chosin Reservoir, North Korea, on 27 November 1950. His remains were not recovered. His name is inscribed on the Courts of the Missing at the Honolulu Memorial.

McClellan was awarded the Purple Heart, the Combat Action Ribbon, 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.