Claim: Vito Corleone is a father.

Santino `` Sonny '' Corleone is a fictional character in Mario Puzo 's 1969 novel The Godfather and its 1972 film adaptation . The character also appears in various flashback sequences in the film 's 1974 sequel , The Godfather Part II .   In the novel and film , he is the oldest son of the mafia don Vito Corleone and Carmela Corleone . He has two brothers , Fredo and Michael , a sister , Connie , and an adopted brother , Tom Hagen . In the film , Sonny was portrayed by James Caan , who reprised his role for a flashback scene in Part II . Director Francis Ford Coppola 's son Roman Coppola played Sonny as a boy in the 1920s scene of that film .