Private First Class Allen was a medic with the Medical Company, 9th Infantry Regiment, 2nd Infantry Division. He was Killed in Action while tending his wounded comrades near Hoengsong, South Korea on 13 February 1951.

Allen was awarded the Purple Heart, the Combat Medical 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.