What movie introduced the character Sonny Corleone?

The movie that introduced the character Sonny Corleone was The Godfather.

Released in 1972 and directed by Francis Ford Coppola, The Godfather is adapted from Mario Puzo’s 1969 novel. Sonny, whose full name is Santino Corleone, is the eldest son of crime boss Vito Corleone and a key member of the Corleone family. James Caan played him in the film.

Sonny is portrayed as a powerful but impulsive heir apparent. His explosive temper and willingness to use violence contrast with the more calculating leadership style of his father and, later, his brother Michael. His fate becomes one of the film’s most memorable turning points after his actions lead to a confrontation with his brother-in-law Carlo.

Sonny also appears briefly in The Godfather Part II, including childhood and flashback scenes. The character’s fictional legacy continues in The Godfather Part III, where Vincent Mancini is introduced as Sonny’s illegitimate son. Sonny’s first appearance, however, is firmly in the original The Godfather.