Private First Class Viera was a member of Company L, 3rd Battalion, 23rd Infantry Regiment, 2nd Infantry Division. He was Killed in Action while fighting the enemy in North Korea on 23 December 1951. His remains were not recovered. His name is inscribed on the Courts of the Missing at the Honolulu Memorial.

PFC Viera was awarded the Purple Heart, the Combat Infantryman's 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.