I believe Lyndon Johnson was also in the Navy, but I don't know what his status was.
LBJ joined the Naval Reserve in 1940 and became the first Congressman to volunteer for active military service on Dec 9, 1941; he had been elected to House at that point and was serving on the Naval Affairs Committee. He was commissioned as a Lieutenant Commander (LCDR) and did a tour of duty in the Pacific inspecting naval bases and filing reports on base status, equipment stockpiles, combat readiness, etc. Basically, he served as somewhat of an unofficial attache to the Congressional committee on which he served.
IIRC during one of his base visits, he wound up on a combat mission on a USAAF B-26 Marauder along with some Army inspections officers. What happened next is disputed. At least one bomber was shot down with aircrew losses, and several other bombers took fire, but some records show that the plane carrying Johnson turned back due to mechanical problems before reaching the combat area. LBJ always claimed his plane took fire, but he was famous for not letting the truth get in the way of a good story.
He was awarded the Silver Star, but none of the other aircrew aboard the airplane were awarded anything. IIRC I've read one historian describe it as "the most undeserved Silver Star in Naval history."
LBJ left active duty and rejoined the Reserve in 1942. He was promoted to Commander in 1949 and resigned from the service in 1964.