John F. Fontron enlisted in the 301st Ordinance Regiment at Camp Sutton, North Carolina in April of 1942. He served with the 9th Armored Division at Camp Funston (Fort Riley), Kansas. He was commissioned to the rank of First Lieutenant JAG on December 16, 1942. Major John F. Fontron served in the Chief of Military Justice section of the Judge Advocate General Department branch office in New Delhi, India; formerly staff judge advocate at Karachi, India. In May of 1943, he was shipped overseas to Australia and New Guinea; being injured in Australia. He returned to the United States in April of 1944 for hospitalization at Santa Barbara, California and Winter General Hospital in Topeka, Kansas. He was sent overseas again in November of 1944 to India. He was discharged from military active duty in February of 1946.