Private First Class Sims was a member of Headquarters and Headquarters Company, 21st Infantry Regiment, 24th Infantry Division. He was taken Prisoner of War while fighting the enemy near Chochiwon, South Korea on 10 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.

Sims was awarded the Combat Infantryman 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.