Captain Granberg was the pilot of a F-80C Shooting Star fighter interceptor with the 9th Fighter Bomber Squadron, 49th Fighter Bomber Group. On March 30, 1951, while on a combat mission five miles northeast of Sunchon, Korea, he was trying to avoid heavy anti-aircraft fire and ran into a hill. He was listed as Missing in Action and was presumed dead on December 31, 1953. His name is inscribed on the Courts of the Missing at the Honolulu Memorial.