Gene Forrester The narrator, Finny's roommate and best friend. Gene unfolds the painful story of his growth in a New England prep school during World War II, when his jealousy caused Finny's tragic fall.
Phineas (Finny) Gene's roommate and best friend. A gifted athlete, Finny represents freedom and good nature. His fall from the tree ends his competition in sports and ultimately costs him his life.
Elwin Lepellier (Leper) A shy student with an interest in nature and skiing, a friend of Gene's. The first Devon student from his class to enlist, Leper suffers a mental breakdown in the army. Leper's memory of the fall reveals Gene's guilt to Finny.
Brinker Hadley A student leader, friend of Gene. When Finny leaves school to recover from his fall, Brinker temporarily takes his place as Gene's closest friend. Controlling and aggressive, Brinker organizes the "investigation" into Finny's accident that becomes, in effect, Gene's trial.
Mr. Hadley Brinker's father, who appears near the conclusion of the novel. Mr. Hadley's hearty enthusiasm for the war makes clear the distance of the older generation from the boys, who view the war and their part in it with reluctance and dread.
Mr. Prud'homme A Devon master, or teacher. Charmed by Finny and lulled by the casual atmosphere of the Summer Session, he does not enforce the usual school discipline.
Mr. Ludsbury A strict Devon master, a contrast to Mr. Prud'homme. During the Winter Session, he strives to bring the boys back to the traditional rules. He represents discipline and devotion to duty.
Dr. Stanpole The school physician. He cares for Finny in the infirmary after his accident and performs surgery to set Finny's leg, an operation that Finny does not survive. Responsible and capable, Dr. Stanpole nevertheless cannot help the young man. His failure reflects the powerlessness of older adults at a time of war.
Phil Latham The wrestling coach who assists Dr. Stanpole when Finny falls the second time. He offers to talk with Gene about Finny's accident, but Gene changes the subject. Like Dr. Stanpole, Latham represents the sympathetic, but powerless, adult.