Jack Nicholson
Jack Nicholson began his career as a collaborator with Roger Corman, the camp horror director, after visiting his sister in Hollywood and working in the offices of Hanna Barbera. He became a breakout star in the 1960s. At first Nicholson was poised to become a writer/director, but his starring turn in Easy Rider established him as a successful actor and earned him his first Academy Award nomination. He then went on to star opposite Karen Black in Five Easy Pieces, and in Mike Nichols' film Carnal Knowledge, Hal Ashby's The Last Detail, and Roman Polanski's Chinatown, before landing the career-defining role of Randle McMurphy in One Flew Over the Cuckoo's Nest. Other defining roles include the murderous father in Stanley Kubrick's adaptation of Stephen King's The Shining, James L. Brooks' Terms of Endearment, The Postman Always Rings Twice, Reds, Prizzi's Honor, A Few Good Men, As Good As It Gets, About Schmidt, Something's Gotta Give, and The Departed. He is known as a great film antihero and maverick, often playing heroic characters with humor, humanity, and a glint of madness.
Louise Fletcher
Fletcher won the Academy Award for her performance as Nurse Ratched, a role that she auditioned for many times. Forman offered it to a number actresses before her, including Jane Fonda, Ellen Burstyn, and Anne Bancroft. She has stated in an interview that while Jack Nicholson was making a large salary, all the other actors were paid scale, and she was paid $10,000 before taxes for eleven weeks of work. One of the first audiences of the film cheered when Nurse Ratched was strangled. Ratched was a relative unknown, having had small guest roles on television roles, but Cuckoo's Nest catapulted her into the public eye. Forman has said that he liked Fletcher's performance of Ratched because she does not realize how evil she is; she is simply trying to do her job.
Will Sampson
Will Sampson was the Native American actor chosen to play "Chief" Bromden. At 6'7", Sampson was perfect for the imposing figure of Chief. The producers discovered him while he was working on the rodeo circuit, in spite of his never having acted before. He was also a painter.
Brad Dourif
A consummately unusual character actor, Dourif's breakout role was in Cuckoo's Nest. He stated in an interview about the role, "I tried to make Billy wide open. He wanted to be part of everything, and that made him scarier and more vulnerable." He received an Academy Award nomination for his performance. Later in his career, Dourif was a frequent collaborator of auteur Werner Herzog. Oddly enough, Dourif also stars as Chucky in the eponymous movies.
William Redfield
Redfield was a New York theater actor who frequently appeared in film and television as well.
Sydney Lassick
Christopher Lloyd
A stage actor early in his career and a student of the renowned acting teacher Sanford Meisner. His role as the belligerent Taber in Cuckoo's Nest was his first film role. His most famous roles include his role on the television show Taxi and as the eccentric "Doc" in the Back to the Future films.
Danny DeVito
Having appeared in the off-Broadway production of Cuckoo's Nest, DeVito was the only cast member to be transferred from the stage version, and the first actor cast in the film. Like Christopher Lloyd, he went on to star in the television show Taxi, before having a prolific career as a film actor.
Dean Brooks
Brooks did not have to prepare as much as the other actors, as indeed he was the actual director of the Oregon State Hospital, where the movie was filmed.
Scatman Crothers
The unusual name of "Scatman" was given to him by a director at a radio station in Ohio to make him more distinctive. It refers to "scat" singing, though Crothers had not yet developed this talent. Crothers would later embark on a prolific film and television career.