The film begins with still photos of the Model T Ford being introduced to the world. A symbol of the time changing in America. A new industrial age is upon everyone. We see Red with his family reciting poetry at their dinner table, and Charles Howard become a successful car salesman in California, while Tom Smith is seen as a loner who knows how to tame wild horses. This comes just before the Great Depression. After the crash on October 29, 1929, the people of America lose everything. Howard then loses his son in a car accident and his marriage falls apart after and they get a divorce.
Red's father gives him to a man who owns horses and has a home for his son there and work. He is seen battling through his life doing anything he can to earn a living, from caring for horses, racing them and even boxing. Howard goes to Tijuana, Mexico in order to finalize his separation with a divorce. Here he meets Marcela and the two fall in love and get married. Howard decides to purchase a horse and while in the process he meets Tom Smith and comes to like him as Tom has a horse with a broken ankle he refuses to put down just because it's hurt. He hires him to help him find a race horse.
Tom discovers Seabiscuit, a wild horse that has had losing trained into his blood, but Tom sees in this horse something very special and he convinces Howard to buy him. Later Tom sees Red fighting a group of men as Seabiscuit is bucking off multiple men trying to tame him, and he pairs the two together. Seabiscuit and Red hit it off from the get go, and they begin to train the losing mentality out of the horse with Tom. As they do, we begin to see that Seabiscuit is special and he begins to win race after race.
Howard then challenges millionaire Samuel Riddle to let his undefeated horse, War Admiral race against Seabiscuit, but Riddle doesn't bite. Not until Seabiscuit loses by a nose does Riddle set up a head to head race with him. We learn that Red is blind in his right eye and this is why Seabiscuit lost the race as Red couldn't see the horse coming up from behind him on the right. Tom is angered, and wants to fire Red, but Howard won't. Just as Tom wouldn't put down a horse because it was banged up, Howard won't put Red down either.
Seabiscuit faces War Admiral head to head at Pimlico Race Course, War Admiral's home track. Before the race Red is asked by the man who hired him as a child to ride his horse for potential buyers, and is thrown off violently. Red's leg is shattered and he isn't able to ride. He won't allow Howard to scratch and tells them to call in his friend and jockey-great, Woolf who rides Seabiscuit to a win by multiple lengths and becomes a hero to the people of America as he represents them being able to get through the hardships of the Depression.
In a race at Santa Anita, Woolf is riding Seabiscuit, who tears a ligament during the race and has to pull up. Howard won't let the doctor put him down. Red helps the horse to get back to being healed and Seabiscuit helps Red to heal as well. Before long Howard enters Seabiscuit to run at Santa Anita once again where Red will ride him. Seabiscuit falls behind terribly, but Woolf drops back on another horse he is riding so that Seabiscuit can see his competition which always make him race faster. Seabiscuit goes on to win the race.
