Randle P. McMurphy - Played by Jack NicholsonThe cocky convict and rebel-hero of the film. With his wild hair, boundless energy, loud mouth, foul language, pornographic playing cards, ready laugh, and physical courage, McMurphy challenges authority in the mental institution. He encourages the men on the ward to laugh, learn, and stand up for themselves. He gives them playful nicknames: Chezzer, Tabelation, and Hard-on (for Harding). Generosity is his hallmark, and he shares whatever he has—gum, cards, games, fishing, booze, even his girlfriend.

Nurse Ratched - Played by Louise FletcherThe stiff, starched head nurse and antagonist of the film. Nurse Ratched’s every physical movement and facial expression is measured and contained: her cap is perfectly white, her voice is polite and controlled, her face is stony, and her expression is unsmiling and cold. Her tightly rolled hairstyle suggests horns, lending a visual weight to her role as McMurphy’s enemy. She displays a frightening cruelty, all the more chilling for her calm delivery.

Chief Bromden - Played by Will SampsonThe huge Native American mental patient who pushes a broom silently while observing everything that happens in the ward. Everyone thinks the Chief is a deaf-mute, nearly comatose, and unable to interact. His hair is long, his face solemn, and his eyes sad. McMurphy says he is big as a mountain, and he is nearly as silent, solid, and strong.

Billy Bibbit - Played by Brad DourifA stammering, suicidal young man with a fixation on his mother. Billy is tentative, inhibited, virginal, gentle, and sweet. Long curls fall over his forehead to accentuate his childlike quality. When threatened, he cringes and cowers to make himself smaller, hugging himself into a ball. He attaches himself to McMurphy as a devoted follower.

Harding - Played by William RedfieldAn intellectual patient who has problems with his wife and his sexuality. The thoughtful, articulate Harding is the leader of the ward until McMurphy appears. He follows the rules, answering Nurse Ratched’s questions in group therapy and taking his medication without complaint. He wears a mustache, along with a prissy expression, and loses his self-control only when Taber pokes at him physically or verbally. Nurse Ratched feels especially threatened when even the obedient Harding begins to side with McMurphy.

Cheswick - Played by Sydney LassickAn anxious, fretful patient whose brow is always wrinkled in concern. With thick glasses framing his worried eyes, the diminutive Cheswick sometimes holds his breath and screws up his features until he looks like he will explode. His sense of fairness is easily frustrated, and he comes to Harding’s aid even when Harding rejects Cheswick’s assistance. McMurphy trusts Cheswick to drive the boat during their unauthorized fishing trip—before Cheswick can panic, McMurphy calms him by evoking the happiness of childhood as he sings “I’m Popeye the Sailor Man.”

Martini - Played by Danny DeVitoAn inmate with a dim, foolish smile and infantile manner. Although Martini is unable to follow even the simplest rules in a game of cards or Monopoly, he loves to play and is always ready for fun. His mouth twitches and grimaces when Nurse Ratched makes him uncomfortable. Martini is fascinated by McMurphy from the moment McMurphy shows him the deck of dirty cards. Martini provides many of the comic moments of the film and is one of McMurphy’s most loyal followers.

Taber - Played by Christopher LloydA hostile, belligerent, and profane patient. Taber delights in poking at Harding with ridicule and physical jabs. One of the funniest scenes in the film shows Harding finally getting even with Taber by hiding a lit cigarette in his cuff. When Taber begins to shriek and jerk around, the orderlies think he is having a lunatic fit, but actually his ankle is burning. Taber’s long face moves rapidly from confusion to amazement to delight, and it is his series of expressions, as well as his laugh, that ends the film.

Dr. Spivey - Played by Dean R. BrooksThe administrator of the mental institution. Dr. Spivey is a calm, mature, gray-haired doctor. McMurphy plays to Dr. Spivey’s vanity, as illustrated by a photo of a prize Chinook salmon on his desk. Dr. Spivey expresses doubt that anything is wrong with McMurphy’s mind, but he defers to the opinion of Nurse Ratched, for whom he expresses the highest regard.

Candy - Played by Marya SmallMcMurphy’s pretty, easygoing girlfriend. The good-natured Candy is willing to go along with all of McMurphy’s schemes. She asks the patients on the bus whether they are all crazy but does not judge them when they nod yes. She is gentle and understanding with Billy Bibbit and provides him with his first sexual experience.

Nurse Pilbow - Played by Mimi SarkisianThe nurse who carries out Nurse Ratched’s directives. Attractive and young, Nurse Pilbow shadows Nurse Ratched closely and administers the patients’ medications. She wears a pink coat in contrast to Nurse Ratched’s black one. She seems to believe that the medication she gives McMurphy is good for him. Unlike Nurse Ratched, Nurse Pilbow shrieks at the unexpected, whether it is McMurphy appearing inside the nurse’s station or Billy Bibbit lying with his throat cut.

Orderly Turkle - Played by Scatman CrothersThe night orderly in the mental hospital. Turkle accepts McMurphy’s bribes of cash, alcohol, and the promise of a blonde, and he willingly lies to the night supervisor with phony respectfulness. He turns a sly, blind eye to McMurphy and Candy in his eagerness to be with Rose. When he gets caught with a woman by the night supervisor, he gives up all hope of controlling the inmates and drinks himself to sleep.

Attendant Washington -  Played by Nathan GeorgeThe lead attendant. Washington enforces Nurse Ratched’s rules and exercises authority through discipline. He does not mind using force, gladly tightening a strap around his knuckles to threaten McMurphy. He enjoys manhandling the patients and pokes McMurphy with a pole simply to emphasize his authority.

Warren - Played by Mwako CumbukaThe second attendant. Warren’s physical presence helps keep the patients in line. He does Nurse Ratched’s bidding without comment.

Scanlon - Played by Delos V. Smith Jr.A bushy-haired, heavily bearded patient. Scanlon is a speechless presence during most of the film, so it is surprising when, in a group session, he challenges Nurse Ratched about being locked out of the dormitory.

Sefelt - Played by William DuellA short, quiet patient. Sefelt slips his own medications to his buddy and is the first to spread the rumor that McMurphy has escaped.

Frederickson - Played by Vincent SchiavelliSefelt’s tall, quiet companion. Fredrickson has a lost, loony expression in his dark eyes but laughs eagerly at McMurphy’s antics.

Bancini - Played by Josip ElicA tall, quiet patient who repeatedly claims he is tired. Bancini allows McMurphy to ride him like a horse in order to teach the Chief how to shoot a basketball.

Colonel Matterson - Played by Peter BroccoA wheelchair-bound patient, presumably the oldest in the ward. The Colonel is one of the “chronics,” who do not interact with others. During McMurphy’s Christmas party, Martini decorates the Colonel with ornaments, and he has as much fun as everyone else.

Rose - Played by Louisa MoritzA giggling, blowsy friend of Candy’s. Rose helps distract Turkle during the party and later dances with the infantile Martini’s head on her breasts.

Night Nurse - Played by Kay LeeThe supervisor who investigates the ward on the night of McMurphy’s party. The night nurse is an older woman with severe gray hair. Her observant eyes and no-nonsense manner serve as one more reminder that authority watches day and night.

Nurse Itsu - Played by Lan FendorsThe nurse who administers McMurphy’s electroshock therapy. Nurse Itsu has a beautifully soothing voice and gentle manner at odds with the torture she inflicts.

The Harbormaster - Played by Mel LambertThe authority figure on the dock during McMurphy’s fishing escape. The harbormaster turns away from McMurphy’s fanciful storytelling with suspicious disbelief and alerts the hospital.

Ellsworth - Played by Dwight MarkfieldA patient who loves to dance alone in the ward. Only at the party is Ellsworth allowed to dance to his heart’s content.

Miller - Played by Alonzo BrownThe third and beefiest orderly. Miller is always seen with the other two orderlies, which contributes to the sense that they are not individuals so much as a single arm of authority.