Private First Class Penniston was a member of Company H, 3rd Battalion, 7th Marines, 1st Marine Division. He was Killed in Action while fighting the enemy at combat outpost "Frisco" in North Korea on 6 October 1952.

Penniston was awarded the Purple Heart, the Combat Action Ribbon, the Naval Unit Citation, 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.