Master Sergeant Valencio was a member of Company L, 3rd Battalion, 8th Cavalry Regiment, 1st Cavalry Division. He was Killed in Action while fighting the enemy near Unsan, North Korea, on 2 November 1950. His remains were recovered in 2002 and were identified on 24 July 2008. His name is inscribed on the Courts of the Missing at the Honolulu Memorial.

For his leadership and valor, Master Sergeant Valencio was awarded the Bronze Star Medal, 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.