To answer your question: He didn't serve in the military.
It's a common misconception that he did, but according to his obituary with the Los Angeles Times at
http://articles.latimes.com/2003/oct/23/local/me-elam23
, he was exempt from military service during World War II because he was blind in his left eye, the result of being stabbed with a pencil at a boy scout meeting when he was 12, and worked as a civilian for the Navy in Culver City, California for two years during the war.
That being said, in WWII, people were enlisted or drafted with physical deformities that wouldn't be allowed today.
These were the draft regulations in early 1942.
Men classified as 1-B because of minor physical defects are eligible for conscription. There are about 1,500,000 of them. They have no dependents; are not engaged in war work, and are eligible for limited military service, if not for combat duty. Many may be fit for frontline duty within a few months of Army training.
In WWII, if you were an adult male, you could be illiterate, borderline mentally handicapped and missing some minor body parts and there was still a possibility the military would take you because the main requirement was a strong back, the ability to march, follow orders and submit to military discipline. There was always someplace they could stick you. There were men missing fingers who were either drafted or enlisted. But being blind in one eye apparently did exempt one from military service.