An American character actor known for his intense performances, he gained early acclaim for his role as Billy Bibbit in "One Flew Over the Cuckoo's Nest" (1975), earning an Academy Award nomination. His career spans film, television, and stage, with notable roles including Gríma Wormtongue in "The Lord of the Rings" series and the voice of Chucky in the "Child's Play" franchise. With a distinctive style, he's celebrated for bringing complex, often unsettling characters to life across various genres.