Two mimes, Comedy and Tragedy, open a trunk. Tonio, a member of an itinerant touring troupe, emerges. Tonio tells the audience that though they are seeing a play, they should remember that actors, even clowns, are real people who suffer and live lives of agony as well as joy.
The curtains rise on a village in Calabria where the town greets the arrival of the players: the leader Canio, his wife Nedda, and two other clowns, Tonio and Beppe. Canio invites everyone to their performance that night, and the villagers invite him to have a drink with them. One man makes a crack about Tonio having a chance to seduce Nedda. Canio, instantly serious, tells him that nothing relating to his wife is a joking matter.
When he leaves, Nedda is at first frightened that Canio might know something of her activities, but then she is entranced with the birds and sings of their freedom. Tonio listens to her carefree song and, consumed by desire, begs her to love him. She treats him as the clown in their play. When she realizes that he is serious, she turns nasty, eventually striking him. He furiously leaves her just as her lover, a townsperson named Silvio, rushes in. Despite his passionate pleas, Nedda refuses to elope with him immediately. Frustrated, Silvio becomes angry. She finally agrees to leave Canio, and they sing rapturously of their love:
Tonio, smarting from Nedda’s rejection, returns and sees the lovers. He rushes off to the village to get Canio. The two lovers plan to elope that night, and Canio comes in just as he hears Nedda sing that on that night she will be Silvio’s forever. She does not use his name. Canio screams and chases the younger man who escapes. Tonio laughs at the furious Nedda; when Canio returns, she refuses to give him her lover’s name. She goes off to prepare for the show; Beppe tells Canio that he must prepare as well.
Thinking of Nedda’s betrayal, Canio sings of his suffering—that he must play the clown although his heart is breaking.
Canio dreams of his younger days with the circus.
The villagers are eager for the standard play: a young woman, married to an older man, is in love with a young man. She plays at being nice to her husband but really seeks the young man, and in the end the husband accepts the situation. The play opens with scenes of Nedda with Tonio and their happy romance. Canio, as the clown, enters just as Nedda sings the exact words he heard her say to her lover an hour or so earlier. It is too much. She desperately tries to keep him in the play, but after two or three more moments, he explodes, telling Nedda that he is serious. The crowd is rapt as he sings, “No, Pagliacci non son.”
Nedda tries for a few moments to bring Canio back to the play, but all he can do is to demand the name of her lover. She finally explodes, crying that she will never tell him. Blind with rage, he stabs her. Silvio breaks from the crowd; Canio sees him and stabs him. The opera ends with the immortal line, “The comedy is over.”