Gary McAfoose was born on April 11, 1950, in Indiana, Pennsylvania. He was drafted into the U.S. Marine Corps and began active duty on September 24, 1969. After attending basic training at Paris Island, South Carolina, and Infantry Training at Camp Lajune, North Carolina, McAfoose was trained as a truck driver at Camp Pendleton, California. He was assigned to the 3rd Marine Aircraft Wing at MCAS El Toro, California, in April 1970, and deployed with the Wing to Da Nang AB in the Republic of Vietnam in June 1970. McAfoose returned from Vietnam in December 1970, and served with the 1st Marine Aircraft Wing from February to April 1971. LCPL McAfoose received an honorable discharge from active duty at Camp Pendelton, California, on June 16, 1971, and was discharged from the Marine Corps Reserve on September 23, 1975.