Private First Class Villereal was a member of Company C, 1st Battalion, 38th Infantry Regiment, 2nd Infantry Division. He was taken Prisoner of War while fighting the enemy in South Korea on 12 February 1951. He was presumed dead on 19 January 1954. His remains were not recovered. His name is inscribed on the Courts of the Missing at the Honolulu Memorial.

Villereal was awarded the Purple Heart with Oak Leaf Cluster, the Combat Infantryman's 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.