Private First Class Villanueva was a medic with the Medical Company, 31st Infantry Regiment, 7th Infantry Division. He was Killed in Action while tending his wounded comrades in North Korea on 2 September 1951.

Villanueva was awarded the Purple Heart, the Combat Medical 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.