Corporal LeMatty was a member of Battery A, 63rd Field Artillery Battalion, 24th Infantry Division. He was taken Prisoner of War while fighting the enemy along the Kum River, South Korea, on 14 July 1950, forced to march to North Korea on the "Tiger Death March" and died during the march between Manpo and Chunggang-jin, North Korea, on 1 November 1950. His remains were not recovered. His name is inscribed on the Courts of the Missing at the Honolulu Memorial.

LeMatty was awarded 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.