Federico Fellini, co-author of the treatment, was the first person Salvatores met at Cinecittà at the beginning of the shoot for his debut film. Fellini was filming And the Ship Sails On and asked Salvatores what his profession was. When Salvatores replied, "director," Fellini placed a hand on his shoulder and said, "Courage!"
When Fellini and Pinelli wrote the treatment that Gabriele Salvatores used as the basis for the screenplay, they had not yet been to America. Salvatores chose to depict New York in a not entirely realistic way to capture the sense of idealization.
Once Upon a Time in America, referenced through the famous shot of the Brooklyn Bridge, is one of director Gabriele Salvatores' favorite films.
The first part of the film, which closely follows the treatment written by Fellini and Pinelli, is shot in a neorealist style. Later in the film, there is a screening of Paisà by Roberto Rossellini, a masterpiece of the neorealist genre, to which Fellini himself had contributed. In Napoli - New York, the American success of the film serves as a counterpoint to the disdain with which Italian immigrants were received.
The line "Where are you from? Africa?" is the same as the one in Rocco and His Brothers by Luchino Visconti, which also deals with the theme of migration.