Private First Class Fallon was a Light Weapons Infantryman with Company F, 2nd Battalion, 35th Infantry Regiment, 25th Infantry Division. He was taken Prisoner of War while fighting the enemy in South Korea on 22 July 1950, forced to march to North Korea on the "Tiger Death March", and died while a prisoner at Hanjang-ni, North Korea, on 2 February 1951. His remains were not recovered. His name is inscribed on the Courts of the Missing at the Honolulu Memorial.

Fallon was awarded the Purple Heart, the Combat Infantryman's Badge, 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.