Seabiscuit: An American Legend has sold more than three million copies and topped the New York Times bestseller list for forty-two weeks. In addition, the book won a variety of awards, and was a finalist for the coveted National Book Critics Circle award. The book was also named one of the best of 2001 by National Public Radio, the Washington Post, Time magazine, and Amazon.com, among others.

Critical appraisal could find little wrong with Hillenbrand's first book-length effort. Patsy Gray, writing in Library Journal, writes, "This story of trust, optimism, and perseverance in overcoming obstacles will appeal to many readers." Todd McCarthy of Variety contends that part of the work's allure is due to the horse being "a commoner among racing's royalty, which ultimately became the source of his mass appeal." A reviewer for Publishers Weekly called the work a "captivating account of one of the sport's legends" rendered in "simple, elegant prose." Dennis Dodge, writing for Booklist, proclaimed the work "a remarkable testament to what four years of meticulous research and a writer's gift for storytelling can accomplish." Others noted Hillenbrand's craft, imagery, and poetic word choice. Even Business Week, not known for flowery praise, included a glowing review that complimented the author as "a deft storyteller whose descriptions of such races are especially good, filled with images of pounding hooves and splattering mud."

A significant number of reviewers noted the parallels between Hillenbrand's own condition (Chronic Fatigue Syndrome) and the perils illustrated in the work. One of the more thorough analyses, penned by Tim Morris in Aethlon: The Journal of Sport Literature, noted the success of Hillenbrand's work as unlikely as the success of its protagonist, and compared the reading public's encouragement of Seabiscuit to overcome the odds against him to Hillenbrand's need to defeat her disease. Morris explored fans' online postings to Hillenbrand and discovered a significant "crossing over" of the fan base from those who enjoyed the work to those who were aware of her condition. The essayist pointed out, "The book evokes a culture that has vanished for good, where noble animals and noble men and women commanded the nation's attention by competing in a pure and elemental sport."

Rarely does any work garner such positive reinforcement from both the reading public and professional critics alike. Seabiscuit filled a nostalgic void much needed in the modern world, and reinforced a nation's belief in persistence as the route to ultimate success.