Fred McMurray never played a villain, except in The Apartment, where’s he’s a slimy ratbastard. (It could also be in Double Indemnity except that he’s more victimized than villain.)
He’s also exposed as the real bad guy at the end of “The Caine Mutiny.”
“Once Upon a Time in the West” is the only movie I can think of in which Henry Fonda was an unalloyed villain… but he was also cast agaiunst type in “Fort Apache.” In that one, John Wayne is the thoughtful, peaceful cavalry officer who wants to avoid a fight with Cochise and Geronimo. Fonda is the cold, cruel, arrogant warmonger.
Did Jimmy Stewart every play an actual bad guy? His “good guy” characters often showed a hint of anger, violence, cruelty or even madness… but I don’t think he ever played a true villain.
In After the Thin Man, he plays a murderer who kills the husband of the girl he’s in love with, and then tries to frame her for the killing to get back at her for not marrying him. Even here, though, he’s a sympathetic characters for most of the film, and even after it’s revealed that he’s the killer, he’s so obviously deranged that you still feel sorry for him.
Oh, she hardly counts for this thread, after all the people she offed in Murder, She Wrote.
What, you think it’s just a coincidence that all those people die violently whenever she’s around? Cabot Cove had the highest murder per capita rate in the world, approaching nearly 1:1. Don’t tell me she wasn’t behind that!