Alan Alda
Alan Alda starred in M.A.S.H., a show following shenanigans of military men living on a base, but he had some real-life experience. He was in the ROTC program in college at Fordham University, receiving a degree in English. Following graduation, for six months real-life Alan Alda served in Korea as a gunnery officer. His character on the television show played a medic in the Korean War.
Steve McQueen
Once nicknamed, "The King of Cool" Steve McQueen was also pretty slick when he served in the United States Marine Corps. Though his relaxed attitude worked in acting auditions, it didn't go over so well in the service. Steve was demoted over 6 times due to his disregard for rules and authority figures. He was once even arrested for taking an unapproved vacation, though he was redeemed by saving 5 drowning soldiers.