When Mae visits Jimmy Braddock in the locker room before the Max Baer fight, his left suspender is in a different position from each angle.
Braddock must pick up the bowl to eat before the fight because he has no spoon. However, a spoon is clearly visible on the table. He isn't supposed to have a spoon until later in the film.
When Jimmy Braddock first shows his wife the $175 his manager gave him so he could train and get back into shape, he holds the money between his index finger and his middle finger. In the next shot, he holds it between his thumb and his index finger.
When Jimmy Braddock wins his first comeback fight, Braddock turns and looks at Gould before Gould calls out his name as he is climbing into the ring.
Max Baer wears a robe with his name on the back. In reality, the robe Baer wore to both of his title fights was a prop from The Prizefighter and the Lady (1933). Baer played a character named "Steve Morgan", so that was the name on the robe.
Contrary to the way it was portrayed in the film, The New York Times called the Baer-Braddock fight "one of the worst heavyweight championship contests in the long history of the ring," noting that Baer, "ever the clown, didn't want to fight" and "could not be serious, even as a fortune was slipping through his fingers."
Braddock, Gould, and the radio announcer call the Madison Square Garden Bowl "The Garden." That nickname was reserved for Madison Square Garden itself. The Bowl was an outdoor arena in Queens.
The opening scene is set in late November in the New York Metro area. Characters sit outside on patio at night without coats, and the trees and grass are still green.
After the opening fight in the late 1920s, James goes home to his wife Mae and their three kids. Braddock and Mae got married in 1930.
When Braddock watches footage of Max Baer killing Frankie Campell in the ring, two people start to pick up Frankie's body. His left arm starts to slide off his body until he raises it slightly for a moment.
When the family enters the apartment after the electricity has been turned on again, Jimmy Braddock is the only one with snow covering his hat and jacket. The rest of the family has no snow on their outer clothes.
When Mae and the kids see a man leaving his wife while they're out stealing wood, the man walks past a modern blue USPS postal collection box. In the 1930s, the boxes were olive-drab-colored and square.
When the Braddocks enter the fancy restaurant, the band plays an ebullient version of Opus One--which came out in 1944.
The credits list Benny Goodman's version of "Don't Be That Way" as the song playing in the club when Jimmy Braddock meets Max Baer. That version of the song was first performed and recorded in 1938, at Carnegie Hall.
In 1933, Jimmy Braddock reports a dream of dining at the Ritz with Mickey Rooney. In 1933, Rooney was 13-year-old Mickey McGuire, who starred in an series of comedy shorts. Rooney became a major star and household name in the late 1930s.
In one shot of Joe Gould sitting in his car, the leaves of a palm tree are reflected in the automobile's window. This scene takes place in the completely palm-tree-less New York/New Jersey area.
The receipt that Jimmy Braddock gives at the welfare office is about $50 off from the actual amount that Braddock had borrowed. Russell Crowe pointed this out to the director who decided to 'leave it in to prove that it's just a movie'.
During the press conference before the Max Baer fight, one reporter identifies himself as being from the New York Herald. That paper merged with the New York Tribune in 1924, becoming the Herald Tribune.