Sidney Lumet was the first choice to direct this film, and it was his idea to make the characters Cuban and to include the 1980 Mariel harbor boat lift in the story. Unfortunately, he did not feel an affinity with Oliver Stone's screenplay, and he bowed out.
Al Pacino used Meryl Streep's portrayal of an immigrant in Sophie's Choice (1982) as inspiration for his portrayal of Tony.
Al Pacino worked with experts in knife combat, trainers, and boxer Roberto Duran to attain the body type that he wanted for his role. Duran also helped inspire the character, who had "a certain lion in him", according to Pacino.
In the scene where Tony is in the bathtub watching TV, he says to Manny, "Look at dem pelicangs fly." This line was what Al Pacino practiced with a language coach to get the Cuban accent right.
During the scene where Tony and Elvira are sitting in the Cadillac at the car dealership, Al Pacino surreptitiously slips on the hat that Michelle Pfeiffer was wearing while she was looking away, which was not scripted. When she turns back and sees him wearing it, her amused reaction was genuine and to her credit, she stayed in character and ad-libbed a line. Brian De Palma decided to keep that unscripted exchange in the movie to show Elvira's gradual warming up to Montana.
In the final shootout sequence, Al Pacino grabs the gun by the barrel. Although only blanks were used, his hand was badly burned, and production had to be shut down for a few weeks.
Robert De Niro was offered the lead role but turned it down.
This is why I love Al Pacino so much. An Italian-American actor who can so convincingly become a Cuban. I've seen SCARFACE and THE GODFATHER Parts I & II numerous times, and I still have trouble believing that's the same Al Pacino in SCARFACE that was in THE GODFATHER. Truly a chameleon and brilliant actor!