He'll always be Woody Boyd
No matter what role he takes on and no matter how well he does with it, whenever I see him I can only think of his character in Cheers, Woody Boyd.
I have no doubt he's worked hard to avoid typecasting, even to the point of taking on parts that require the polar opposite of that character's naïve innocence. He's seemingly everywhere, and has worked with seemingly everyone over the last 25 years. But it makes no difference, he can only ever be Woody Boyd.
I'm not even an especially big fan of Cheers: it was one of those shows that had its moment in the sun, and is now mostly forgotten. Yet Woody Harrelson has somehow remained ubiquitous. Maybe he's just an easy hire for casting directors.