War: WWII VietnamGlenn Ford interrupted film career to volunteer for duty as Marine in WWII. Joined Naval Reserve in 1958 retiring in the 1970s as captain.
War: WWIIAfter securing a contract guarantee from RKO, Robert Ryan enlisted in US Marine Corps & served as drill instructor at Camp Pendleton, San Diego, CA
War: post-WWIIGeorge C. Scott served as guard at Arlington National Cemetery; taught English literature & radio speaking/writing at Marine Corps Inst (before film career)
War: post-WWIISteve McQueen saved the lives of 5 Marines during Arctic exercise pulling them from a tank before it broke through ice into sea. (before film career)