Sergeant First Class MacClintock was a member of the 187th Airborne Infantry Regimental Combat Team. He was Killed in Action while fighting the enemy in South Korea on 24 March 1951.

MacClintock 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.