Sergeant First Class Villarreal was a member of Headquarters Battery, 15th Anti-Aircraft Artillery (Automatic Weapons) Battalion, 7th Infantry Division. He died of other causes on 12 December 1951 at the 8209th Mobile Army Surgical Hospital.

Villarreal was awarded 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.