1. Marlon Brando did not remember his lines and read his lines from cue cards during his shooting.
2. Al Pacino got angry and proscribed the Academy Awards Ceremony that he was nominated for the Supporting Actor. His point was that he had more screen time than his co-star, Marlon Brando.
3. A young Sylvester Stallone also auditioned for the roles of Paulie Gatto and Carlo Rizzi, but did not get the role.
4. Diane Keaton, Al Pacino and James Caan all got $35000 as their payment.
5. Francis Ford Coppola directed the film because he was in debt to Warner Brothers.
6. Morgana King who was playing the role of the mother of James Caan and Al Pacino who were only ten year younger than Morgana King.
7. Marlon Brando as a prank put weights on the bed under his body, duting an early scene in the movie, when Vito Corlenine comes back home and his people carry him upstairs. He did it to make it tough, for his people to lift him.
8. One of the scene had almost 700 extras and took massive 4 days to shoot. It was the scene where Sonny beats up Carlo (Connie’s husband). The garbage can lid was used in an improvised fashion by James Caan.
9. In one of the scenes where you see Al Martino’s confused reaction, it was for real. The same happened because the smack which Vito Gave Johnny Fontane was not even in the script Marlon Brando improvised the whole sequence. James Caan says “Martino didn’t know wherether to Laugh or Cry”.
10. There were conflicts between Francis Ford Coppola and Paramount, due to which Paramount frequently replaced Coppola. The issues were majorly due to:- Coppola’s inability to come on time on the sets, mounted expenses which made no sense, product and casting bugs (Coppola completed the film much before the schedule and with exceeded budget, which caused such issues).