Second Lieutenant Joyner was a member of the 24th Infantry Regiment, 25th Infantry Division. He was seriously wounded by the enemy in South Korea on 20 August 1950 and died of those wounds later that day.

Joyner 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.