Corporal Troup was a member of Company E, 2nd Battalion, 38th Infantry Regiment, 2nd Infantry Division. He was listed as Missing in Action while fighting the enemy in South Korea on September 1, 1950. He was presumed dead on December 31, 1953. His remains were not recovered. 

Through the work of the Defense POW/MIA Accounting Agency, the remains of Corporal Howard A. Troup were accounted for in 2024. His name is permanently inscribed on the “Courts of the Missing” at the Honolulu Memorial.