Heres another famous actor who was in the Navy during WWI:
He mentored an upcoming promising actor in 1930's Hollywood by the name of John Wayne. Most people recognize him as sheriff Micah on The Rifleman.
I’ve always liked Paul Fix. Fun to see him in his younger days, playing little weasely characters in early-30s b-westerns. Quite a contrast to his solid grandfatherly roles in 60s tv.