During Seabiscuit's Santa Anita Handicap win, he is running dead last early in the race. The charts for the 1940 Santa Anita Handicap show Seabiscuit running no worse than fourth at any point during the race. In fact, he was in perfect striking position around the first turn and down the backstretch.
In one of his voiceovers, Tick-Tock says, "The Iceman Cometh". The phrase itself comes from the Eugene O'Neill play of the same title, which wasn't produced theatrically until 1946 and refers to George Woolf who was called "The Iceman". Though the phrase "The Iceman Cometh" isn't historically accurate, it is likely a reference to Jeff Bridges's role in The Iceman Cometh.
The scenes at Pimlico and Santa Anita Racecourses show ovals equipped with the modern Fontana Safety rail, which is very wide at the top. These rails were not
adopted in the US until the late 1980s. In the 1930s, the rails were narrow.
Before Seabiscuit and Red Pollard's first race, when Seabiscuit is being loaded into the starting gate, you can see the Santa Anita racetrack sign in the background, with a digital scoreboard. Digital scoreboards were first manufactured in the 1980's.
Late in the film, as Charles Howard worries in the bleachers about letting Red Pollard ride in the race, his wife Marcella plays with the marble game. She keeps talking in the next shot, but her lips (at the top of frame) don't move as the audio finishes.
In a wide shot establishing the Pimlico location before the match race with
War Admiral, the Maryland state flag is shown flying upside down. This is a common error in real life due to the unique design of the flag. The black portion of the flag should be on top; not the red portion as reflected in the movie shot.
Seabiscuit continually changes from a light honey bay to a dark reddish bay. He also grows and shrinks throughout the film, and his mane switches sides. A horse's mane falls to one side or the other, it doesn't change from side to side.
When Seabiscuit is being worked out after recuperating from his injury, Charles Howard sees Tick-Tock McLaughlin in the stands, reading a paper. The paper switches back and forth from being closed to opened as the camera moves back and forth between them.
When Red Pollard and Seabiscuit are recuperating, Red asks the track guy to mow around a tree to make a sort of track. The track guy brings out a push mower. The grass he is cutting is higher than the blades. A push mower won't cut grass that high, it will just push over it.
Famed horse trainer James "Sunny" Fitzsimmons is portrayed by Irish born actor Shay Duffin speaking with an Irish brogue. Although he was of Irish ancestry the real Fitzsimmons was born and raised in Brooklyn and had no Irish accent.
During the credits, a printing plate for a newspaper page is shown. The lettering of the story and the headline "MATCH RACE" is the correct way round, whereas a printing plate is a mirror-image of the page that it prints.
In one of the key moments in the film, a tractor misfires and Red Pollard's horse bolts, breaking his leg. The tractor is a John Deere D or GP. It has a flywheel that has to be turned to start the tractor. The sound it makes attempting to "start up" is that of a car engine turning.