Private First Class Hopfensperger was a member of Company B, 1st Battalion, 32nd Infantry Regiment, 7th Infantry Division. He was seriously wounded by the enemy in South Korea on September 23, 1950 and returned to duty on October 1, 1950. He was Killed in Action while fighting the enemy in North Korea on November 28, 1950. His name is permanently inscribed on the Courts of the Missing at the Honolulu Memorial. PFC Hopfensperger's remains have been recovered and identified.