Marlon Brando had said he had based his raspy voice portrayal of Don Vito Corleone in El padrino (1972) on Frank Costello's voice as heard from hearings aired on TV. Robert De Niro who also played a young Vito Corleone in El padrino (parte II) (1974) goes full circle and portrays Frank Costello. However, in this film they stayed away from Costello's raspy voice imitation.
In a 2025 interview with Esquire, Barry Levinson spoke about how Robert De Niro wanted to approach playing the dual role, and how a mystery actor was involved: "He said, 'Look, when we shoot, I don't want to just have the script supervisor reading the lines off camera. We have to get an actor.' So we did, and when Bob would do Vito, that actor would play Frank, and then they would switch over, do the opposite. ...Bob picked him because Bob thought he would be good enough to challenge him. I can't say who it was."
This is the fifth collaboration between Barry Levinson and Robert De Niro after Los hijos de la calle (1996), Escándalo en la casa blanca (1997), Los realizadores (2008) and The Wizard of Lies (2017).
Real-life Vito Genovese and Frank Costello were portrayed in Barry Levinson's movie Bugsy (1991), in which Don Carrara portrayed Vito and Carmine Caridi portrayed Frank.
This movie was originally entitled "Wise Guys," which was almost the title for Buenos muchachos (1990) even though it was spelled Wiseguy.