Tom Hagen — The Godfather Part II (1974)

Duvall reprised Tom Hagen in The Godfather Part II, and while the role is smaller, his scenes with Al Pacino crackle with tension as the consigliere watches Michael Corleone discard the family's humanity in favor of pure power. His final confrontation with Michael — suggesting Hagen is the last thread of the old world — is one of the film's defining emotional beats. He declined to return for Part III after a salary dispute.