During World War II, real life sailor Guy Madison was discovered and signed on to play... a sailor, in the film "Since You Went Away" (1944). Although his appearance in the role was brief, he created such a sensation (look at his pics and you can see why) that when he came back from his tour of duty, he had a ready-made career in film.
Although most critics have been less than generous regarding his acting talent, I have found him to be quite a competent actor - not that that really matters considering his incredible sex appeal. He made quite a few westerns and action-type films, and also starred in a TV series "The Adventures of Wild Bill Hickock" in the early 1950s.
Best role I've seen him in: "Till the End of Time" (1946), as a GI returning home to San Diego, having a hard time finding his place in civilian life after fighting in World War II. [Although not released to DVD (yet?) there may still be some old copies of this movie floating around on VHS.]
Now, here's Guy...