Award Category Fraud: Although the part of Edie Doyle properly is a lead, producer Sam Spiegel listed Eva Marie Saint as a Supporting Actress in the hopes of getting her a nomination. The ploy worked, and she won the Oscar.
Creator Backlash: Even though Marlon Brando won the Best Actor Oscar for playing Terry Malloy, he was embarrassed by his performance. In his autobiography he wrote that when he saw the film for the first time, he became so depressed that after the movie, he left the screening room without saying a word to anyone.
Dawson Casting: Edie Doyle was supposed to be 19. Eva Marie Saint was 30.
Although Rod Steiger plays Marlon Brando's older brother in the film, in real life, Brando was a year older than Steiger.
Executive Meddling: In the original ending, Terry was supposed to be killed by Johnny Friendly and company, but because of The Hays Code, Terry lives and it is implied that the longshoremen triumph over Friendly.
Elia Kazan pointed out that Friendly was still alive at the end, insisting that he'll be back. He said that the ending wasn't meant to be taken literally but more as a resolution to Terry's personal struggle.
Reality Subtext: Elia Kazan had been harshly criticized for reporting names to HUAC during the Red Scare, so he made a film where informing on bad people is the heroic thing to do.
Serendipity Writes the Plot: Sam Spiegel forgot to pay for rear-projection equipment, hence the reason why the cab where Terry and Charlie play out the film's most famous scene has blinds.
Throw It In!: The scene where Terry picks up Edie's glove and puts it on his own hand was a complete improvisation of Brando's after Eva Marie Saint accidentally dropped it during the shot. It has since become one of the more iconic moments of the movie and Elia Kazan even said that the best decision he ever made as a director was not yelling "cut" after it happened.