During World War II, LT.CDR. Garrison served in the Mediterranean as a U.S. Naval Air Corps pilot. During the Korean War, he was a naval flight instructor in Pensacola, Florida. He received the Distinguished Flying Cross and two air medals in World War II. He belonged to the only complete Air Group for night operations which operated from the aircraft carrier Bon Homme Richard in the invasion of Okinawa and Iwo Jima.
He was a member for the Naval Reserves for twenty years and served as Commanding Officer of Fighter Squadron 681 based in Birmingham, Alabama.
Garrison played the flight instructor in a series of flight training films used in the Naval Air Training Command.