The Godfather character SONNY is the eldest son of Don Vito Corleone, the head of a powerful Mafia family. He is portrayed by James Caan in the 1972 film adaptation of the novel. SONNY is hot-headed and impulsive, often taking matters into his own hands without consulting his father. His younger brother Santino, also known as 'SONNY', is portrayed by John Cazale in the film. He is more level-headed than his brother and serves as an advisor to his father.