At a party in his palace, the Duke of Mantua boasts of his way with women. He dances with the Countess Ceprano, and his hunchbacked jester, Rigoletto, mocks the countess’s enraged but helpless husband. The courtier Marullo bursts in with the latest gossip: Rigoletto is suspected of keeping a young mistress in his home. The jester, unaware of the courtiers’ talk, continues to taunt Ceprano, who plots with the others to punish the duke. Monterone, an elderly nobleman, forces his way into the crowd to denounce the duke for seducing his daughter and is viciously ridiculed by Rigoletto. Monterone is arrested and curses Rigoletto.

Rigoletto hurries home, disturbed by Monterone’s curse. He encounters Sparafucile, a professional assassin, who offers his services. The jester reflects that his own tongue is as sharp as the murderer’s dagger. Rigoletto enters his house and warmly greets his daughter, Gilda. Afraid for the girl’s safety, he warns her nurse, Giovanna, not to let anyone into the house. When the jester leaves, the duke appears and bribes Giovanna, who lets him into the garden. He declares his love for Gilda, who has secretly admired him at church, and tells her he is a poor student. After he leaves, she tenderly thinks of her newfound love before going to bed. The courtiers gather outside the garden intending to abduct Rigoletto’s “mistress.” Meeting the jester, they quickly change their story and fool him into wearing a blindfold and holding a ladder against his own garden wall; then they carry off Gilda. Rigoletto, rushing into the house, realizes his daughter is gone and collapses as he remembers Monterone’s curse.