The four stories of The Red Pony center on Jody. In each story, Jody learns an important moral lesson. In the first, he learns that even the incredibly experienced Billy Buck can be wrong, and that something as exciting and promising as a new horse can end in tragedy. In the second, he learns that he can better sympathize with a stranger than his mature, grown-up father can, and that he has a desire to explore that his father doesn't understand. In the third, he is once again confronted with death, but this time he learns that sometimes life comes from death. In the fourth, he learns that his father's sternness and temper can get him into trouble, and that tales of adventure do not add up to a successful, happy life, which complicates his longing to leave the ranch.

Tied up with the theme of Jody's coming-of-age is his changing relationship with his father. As the book opens, we see Carl Tiflin as a man who keeps his emotions hidden. When he does say something kind to Jody it thrills the boy in a way that shows such praise is rare. Jody can see his father only as a powerful man, a sort of mammoth, powerful distant, object. As the stories progress their relationship changes. Through the threat and promise of adventure inherent in Gitano, Jody begins to see that his own imagination is far more powerful than his father's and that his dreams and his father's dreams do not in any way coincide. As Jody grows up he is forced to face his differences with his father and to see his father as a person of faults and limitations. The arrival of Jody's grandfather in the fourth story, further shows Carl's coldness, and the sympathy of the boy for the old man shows what is lacking in his relationship with his father: sympathy, and a desire for adventure.

Throughout The Red Pony, as in his other works, Steinbeck uses spare language to describe both the physical landscape and the actions of his characters. He does not delve into his characters interior lives and instead tries to portray that life through their exterior words and actions. This combination of unadorned prose style and an insistence on representing only what can be seen or heard or felt is a feature of the realism movement, of which Steinbeck is one of the foremost stylists.