Many actors who first became famous in television sitcoms have gone on to become famous movie-star comedians. Much less common, I think, are sitcom stars who later become even more famous for dramatic roles on the silver screen.
The only obvious case that springs to my mind is Woody Harrelson, whose breakout role was the naïve bartender Woody Boyd on Cheers; since the 1990s he’s been an acclaimed movie star, taking mostly non-comedic roles.
I also thought about Bryan Cranston, though I think his case is less clear-cut. His career breakthrough was playing Hal on Malcolm in the Middle, but his most famous dramatic role, as Breaking Bad’s Walter White, is still a television one. Although he later won awards for dramatic roles on film (Trumbo, Argo), I don’t think this work has come close to eclipsing his television roles in the popular consciousness.
I grew up detesting Lucille Ball, hating her shtick. (I’m somewhat humor-impaired and particularly uninclined to find “wince and cringe” humor remotely funny).
Saw her in Yours, Mine and Ours and was startled to see she could be a good dramatic actress.
I usually avoid Adam Sandler for similar reasons but I was quite impressed with his performance in Fifty First Dates
ETA: oops you did say famous for their dramatic movie roles.
Just UK-famous, but Simon Pegg was quite well-known for Spaced, I think, but I think most USAians would know him best for the Mission Impossible and Star Trek franchises, not his comedy films.
I’d say she was known but not famous. She had daughter or friend or girlfriend and ensemble roles, but MAY was what made her famous - where she got the Emmies and the household name status.
I’m not so sure. While the Mission Impossible and Star Trek films are bigger, he wasn’t the main character like he was in Shaun of the Dead and Hot Fuzz. I think many people in the USA who would recognize him as Simon Pegg (and not just “that guy” from Star Trek) would think of his comedy films first.
I never watched Police Squad!, does that count as a sitcom? Leslie Nielsen was famous in a LOT of Dramatic movies before Airplane! set him on the path to comic superstardom. Even his role in The Reluctant Astronaut had him playing a serious character.
Airplane! came before Police Squad and he never really did a famous dramatic roll after Airplane! He went another direction, Dramatic Movie Actor → Washed-up Hasbeen on TV shows like Columbo & Love Boat to Famous Comedic Actor following Airplane!
Police Squad the Show was only 6 episodes. Less run time than the Police Squad Movies.