Gene Forrester and Phineas, or Finny (whom remains without a last name), Brinker Hadley, and Elwin “Leper” Lepellier are the main characters in this novel. The boys all play an important part in the setting of the novel and the overall plot and storyline themselves.

Gene Forrester is what could only be closely described by terms like dweeb, geek, or nerd.  He is studious to the point of perfection and academic success.  He envies the carefree nature of his roommate Finny, whose antics and lack of appreciation for learning somehow cause Gene to develop a slight obsession despite his frustration at him.

Phineas is your average, stereotypical all-American-boy of the eras between 1930 and 1970-ish.  He is extremely adept in sports of all varieties, even coming up with his own on occasion.  He has broken school records and won several athletic awards, but lacks greatly the academic ability of his roommate, Gene.  Finny’s freewheeling nature also prohibits him from accepting the fact that ht e world is at war, though we learn that this is also partly because he was not accepted into any branches of the military, thus injuring his pride.  Oh, also: He dies.

Elwin “Leper” Lepellier is a friend of both Gene and Finny, despite being immensely outcast from his peers most of the time.  Leper is interested in nature and skiing, which may be why he is so excluded by the other students at Devon.  Leper is the first of the Devon boys to enlist in the military, much to the disdain of Brinker Hadley.  Leper, shortly after enlisting, goes insane due to the stress of the military and makes the decision to go AWOL rather than receiving a section 8 discharge that will lable him as insane and keep him from getting a job anywhere in the future.

Brinker Hadley is the main antagonist in the novel, apart from Gene himself.  Brinker strives ceaselessly during the winter session to achieve peace and order at school, but eventually gives up after he becomes depressed when Leper is the first to enlist in the military.  Brinker attempts to blame Gene for Finny’s accident and even goes so far as to hold a mock-trial in order to officially put the responsibility on Gene.  He and Gene later reconcile.