You would probably say that Marlon Brando was the actor who said, "I'll make him an offer he can't refuse." He played the character Don Vito Corleone in the movie The Godfather, directed by Francis Ford Coppola. Mario Puzo wrote both the book, published in 1966, and the film, produced in 1972.
However, the line spoken by Don Vito Corleone in the movie is just a bit different. He says, "I'm gonna make him an offer he can't refuse." It's actually Al Pacino, playing Vito's son Michael Corleone, who said, "I'll make him an offer he can't refuse." Variations of the famous quote appear three times in the movie and in both sequels, The Godfather: Part II and The Godfather: Part III.
Marlon Brando's line occurs when Vito Corleone's godson Johnny Fontane, played by Al Martino, asks his godfather for a favor. Fontane wants to become a film actor and needs Corleone's help to secure the role, since he has already been turned down for it by the producer.
After Fontane comes crying to his godfather, literally, Corleone tells his godson, "I'm gonna make him an offer he can't refuse." Later, the film cuts to a very memorable scene in the film producer's bedroom, where he wakes up next to the head of his own racehorse. No surprise, Fontane gets the part and becomes a movie star.
Al Pacino's line occurs after Michael takes over the family business. Another mobster, Moe Greene, has refused the family's offer to buy his casino. Michael predicts he will change his mind, saying, "I'll make him an offer he can't refuse." Again, no surprise, Greene is soon dead and the Corleone family owns his casino.
An offer may seem like a negotiation; however, the offer in "I'll make him an offer he can't refuse" really isn't a gift or an exchange of services but a death threat, which is why "he can't refuse." Since mobsters are not known for negotiating, this line recurs throughout The Godfather trilogy in idea or words.
For example, Michael tells his girlfriend Kay Adams (played by Diane Keaton) about another time Vito had to help Johnny Fontane, this time to get out of a band contract. Kay asks how Vito got the bandleader to let Johnny go and Michael simply says, "My father made him an offer he couldn't refuse." When Kay asks what the offer was Michael then chillingly spells it out: "Luca Brasi held a gun to his head, and my father assured him that either his brains or his signature would be on the contract."
Film critics and historians have speculated that Fontane's character was based on the dealings of legendary film star and singer Frank Sinatra. While Sinatra was often seen in pictures with mobsters and reported by others as being friendly with them throughout his life and career, he has always denied that this scene was based on him or his actions and has denied his involvement with any mobsters.