Jerusha "Judy" Abbott's life is drastically changed one day when a mysterious and rich benefactor scoops her up from an orphanage - the only home she has ever known - and offers to pay her way through college. Her benefactor has many requests, the two most important being that she uses this opportunity to become a writer, and that she writes him monthly to update him on her studies.
To maintain his air of mystery, he never responds, and requests that Judy only refer to him as Mr. John Smith. Unhappy about this indifferent title, Judy decides to refer to him as Daddy-Long-Legs due to her only knowing that he is quite tall. Chronicling her four years of college, many friendships, embarrassing stories, and quite-funny musings, Judy finds more than an education in her correspondence with Daddy-Long-Legs.