Well, no. He enlisted in the Marine Corps but was medically disqualified. I assume he didn’t make it to boot camp.
How about Gary Hart, who as a 44 year old senator was appointed Lt. Cdr. USNR by Jimmah Carter, and with no prior service at all? IIRC the year was 1979 & Carter was desperate for votes in the Senate.
No, he flunked out of boot camp by wetting his bed, actually.