Corporal Hopper was a member of Headquarters Company, 2nd Battalion, 19th Infantry Regiment, 24th Infantry Division. He was Killed in Action while fighting the enemy in South Korea on July 31, 1950. His remains were not recovered at the time. Through the work of the Defense POW/MIA Accounting Agency, the remains of Cpl. Hopper were accounted for in 2017. His name remains permanently inscribed on the Courts of the Missing at the Honolulu Memorial.