Jennifer Lawrence went from someone who played the sassy teen in a mediocre sitcom to star in 2011 with her Oscar nomination (along with other nominations) in the low budget Winter’s Bone (2010).
Tupac Shakur went from obscure newcomer to star (and icon) in 1991 with his album, 2Pacalypse Now.
Prompted by this thread, I just watched my first episode of Mork and Mindy (ever–I didn’t own a TV set from about 1972 through 1985) and it was pretty horrible. Lame jokes, dialogue predictable about two minutes in advance, awful mugging and pretend-laughter, though Williams was pretty clever, doing his routines and ad libs regardless of the sit-com context. Strange, though, was the fact the show’s premise (alien arrives on Earth, moves in with pretty girl) didn’t arise once in the episode. Mork was just a naive guy who lived with Mindy.