Bob Denver – Willy Gilligan (Gilligan)
Alan Hale, Jr. – Jonas Grumby (The Skipper)
Russell Johnson – Roy Hinkley (Professor)
Jim Backus – Thurston J. Howell III (Mr. Howell)
Natalie Schafer – Eunice "Lovey" Wentworth Howell (Mrs. Howell)
Tina Louise – Ginger Grant (Ginger)
Dawn Wells – Mary Ann Summers (Mary Ann)
Gilligan's first name of "Willy" is not canon, as it was never mentioned in the show and was revealed years later. Neither The Skipper nor the Professor (note use of "The/the" in their references) used their real names much, but they are revealed in the first scene of the pilot (not the first aired episode).
This was a dumb show at the time and remains a dumb show. Nevertheless, the three-season show has seeped into popular culture as much as another three-season wonder, Star Trek. Almost everyone in the country knows the theme song and can handle references to the characters. Most of the actual shows are forgettable, but the basic motif is classic.
The question is now standard, for us Baby Boomers: Ginger or Mary Ann? It's a defining question, like Cats or Dogs? or Who's Your Favorite Beatle? I asked this of Mpls mayor RT Ryback, and he shot back an answer before I finished the sentence.
So, LJers: Ginger or Mary Ann?