Sergeant First Class Pennington was a member of Headquarters Battery, 503rd Field Artillery Battalion, 2nd Infantry Division. He was taken Prisoner of War while fighting the enemy near Kunu-ri, North Korea on 1 December 1950 and died while a prisoner on 30 April 1951. His remains were not recovered. His name is inscribed on the Courts of the Missing at the Honolulu Memorial.

Pennington was awarded the Purple Heart, the Prisoner of War Medal, 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.