The story is that he only went into the military because of his close ties to the Kennedy family and his idolization of JFK - who as we all know was on the PT109. I see he quit bringing up how he shares initials with JFK. He led from the back, meaning he did his level best to stay out of personal danger. As soon as he'd got enough medals - not hard to do for an opportunist - and saw which way the political wind was blowing over here, he used his connections, got the heck out and morphed into a military-hating, war-protesting, lying scuzbag. Then he ran for office.
I'm not sure, but don't think he's ever actually done anything jobwise but join the military and be a politician.