* CastTheExpert: George "the Iceman" Woolf is played by Gary Stevens: a LivingLegend, Kentucky Derby-winning, Hall of Fame jockey. Stevens retired from race riding in 2005, but returned to the sport full time in 2013, and continued to ride at the highest level (with a couple of breaks in between for knee and hip replacements) until retiring for good in November 2018.
* DyeingForYourArt:
** Creator/TobeyMaguire had to slim down to play Red. Keep in mind that this film is made between ''Film/SpiderMan1'' and ''Film/SpiderMan2'' in which he was required to put on some muscles.
** Creator/ElizabethBanks had to dye her blonde hair dark brown to play Marcela Zabala.
* FakeNationality:
** American Creator/TobeyMaguire as the Canadian Red Pollard.
** American Creator/ElizabethBanks as the Mexican Marcela Zabala.
* OnSetInjury: Creator/TobeyMaguire injured his back during filming, which nearly cost him ''Film/SpiderMan2''.
* PlayingAgainstType: Quintessential ButtMonkey StrawLoser Creator/WilliamHMacy as a fast-talking, charismatic radio host.
* PosthumousCredit: Royce Applegate, who had a minor role as Dutch Doogan, was killed in a house fire six months before the film's release.
* ProducedByCastMember: Besides playing Red Pollard, Creator/TobeyMaguire was one of the film's executive producers.
* RomanceOnTheSet: Creator/TobeyMaguire met his jewelry designer wife Jennifer Meyer on the set.
* ThoseTwoActors: Creator/TobeyMaguire and Creator/ElizabethBanks are mainstays of the ''Film/SpiderManTrilogy'' (though [[Film/SpiderMan2 the second film]] of the series was not yet released during this film's premiere).
* UnderageCasting: Creator/ChrisCooper had to be aged for his character to look the part. Because he was over 25 years younger than his character, Cooper's hair was whitened and his hairline was shaved back to show a widow's peak hairline. Cooper, despite being two years younger than Creator/JeffBridges, was made to appear older in contrast.
* WhatCouldHaveBeen:
** The second Santa Anita race, as described in the book, is [[spoiler:simultaneously one of the greatest and most heartbreaking episodes in Seabiscuit's career]], but is missing from the movie.
** Creator/RobertDuvall turned down the role of Charles Howard because he was making ''Film/SecondhandLions''.
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