Private First Class Mangum was a member of the 160th Infantry Regiment, 40th Infantry Division. He was seriously wounded by the enemy in North Korea on 16 June 1952 and died of those wounds later that day.

Mangum was awarded the Purple Heart, the Combat Infantryman 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.