Alexander Ramsay, known as Alec, is a red-haired, freckled teenager who begins his bond with The Black Stallion aboard a ship. Alec feels sympathy for the stallion and offers it sugar, a kindness no one else shows. Despite the stallion's reputation for being dangerous and its attempts to break free from its stall, Alec continues to engage with it. His love for horses and the uniqueness of the Black motivate him. The novel centers on the developing relationship between the compassionate, determined Alec and the wild stallion, exploring themes of courage, self-reliance, growth, beauty, nature, education, cooperation, and competition.

Alec's journey of maturation unfolds throughout the story. Although he is independent from the start, his strength grows as events progress. His bond with the Black defines him, liberating and elevating him. When riding the Black, Alec feels "different," as if in a world of his own. The Black empowers Alec while also needing him, fostering Alec's exceptional self-reliance on the island. He exhibits bravery, hope, and patience in challenging situations, focusing on survival rather than dwelling on regrets or philosophical thoughts. When Alec reunites with his mother in New York, she notices a "calm, self-reliant look" in his eyes.

The themes of nature and beauty are embodied by the Black. While the stallion displays typical equine behavior, it possesses extraordinary abilities. At Belmont, an observer remarks that the Black "made the track record look like it was made by a hobbyhorse!" The Black epitomizes nature's duality—both beautiful and dangerous. It boasts "wonderful physical perfection" paired with a "savage, ruthless spirit." Representing the wild, untamed aspects of nature, the Black challenges Alec to continue growing. Alec is determined, vowing, "I'll control him—one of these days."

Alec's growth is also nurtured by Henry Bailey, the only other significant human character. Henry, a retired jockey, supports Alec's ambition to keep and train the Black. More than a father figure, Henry is a confidant who acknowledges Alec's maturation by proposing they "work together just like partners." While Alec's father instills responsibility through chores to pay for the stallion's care, it is ultimately Henry who guides Alec into adulthood. Before the pivotal match race at the novel's end, Henry tells Alec: "Well, kid, you're on your own now." Speaking as a mentor, Henry embodies the theme of education.

The novel underscores the significance of education. Its role in life is highlighted when Alec successfully identifies, prepares, and consumes island carragheen, thanks to a biology class experiment he recalls. At Flushing, Alec is depicted as being concerned about his grades and is shown attending school. Before the match race, Mr. Ramsay expresses worries about his son's ability to meet his academic responsibilities. Alec agrees to participate in the race "under one condition—that I stay until I finish my exams."

Henry's assistance and Mr. Ramsay's willingness illustrate the recurring theme of cooperation throughout the novel. The central conflict is not between characters, who are mostly portrayed as stereotypes, but in Alec's battle against nature and his efforts to control the Black. Mr. and Mrs. Ramsay—minor characters—do not object to Alec's involvement with Henry and the Black. They seem surprisingly agreeable to Alec owning and riding a stallion described as "untamable." Other characters, mostly minor, share a love for horses like Mr. Ramsay, admire the Black, and facilitate Alec's journey.

The attitude of Tony, the owner of the Black's stablemate Napoleon, reflects the supportive nature of minor characters. Tony harbors no resentment towards Henry and Alec when he learns that old Napoleon, who must work daily pulling a cart of produce, has been spending nights at the Belmont...