Lieutenant Garrison was a veteran of World War II, serving in the European and Pacific Theaters. In Korea he was the pilot of a F4U-4 Corsair fighter with Fighter Squadron 114 (884) aboard the aircraft carrier USS Boxer (CV-21). On 18 May 1951, as he was working with a ground controller, his aircraft was hit by small arms fire. He tried to parachute but struck the tail assembly. He landed and was taken prisoner. He was presumed dead on 24 May 1954. His remains were not recovered. His name is inscribed on the Courts of the Missing at the Honolulu Memorial.

For his leadership and valor, Lieutenant Garrison was awarded the Air Medal with 2 Gold Stars, the Purple Heart, the Prisoner of War Medal, the Presidential Unit Citation Ribbon with Bronze Star, the Combat Action Ribbon, the Korean Service Medal, the United Nations Service Medal, the National Defense Service Medal, the Korean Presidential Unit Citation, the Republic of Korea War Service Medal and several World War II service medals.