The Hobo is a veteran of the Korean War. While in Korea he saw combat regularly, and lost most of his platoon in a friendly fire incident. It's unknown how he first came to Bullworth Academy, but he currently lives in a fenced in yard behind a broken down school bus on the school grounds. He is an alcoholic and spends much of his time either drunk or looking for a way to get drunk. He occasionally has flashbacks to the war, and may suffer from Post-Traumatic Stress Disorder. He is also collecting radio transistors with a great urgency, claiming he needs them to finish a device he's building before it's too late.

At an unknown point in time the Hobo was a member of the Bullworth faculty. He occasionally says he should go back to teaching, and calls Dr. Crabblesnitch a spineless weasel. The nerds mention that he was a former teacher in smalltalk. Miss Danvers occasionally announces over the PA system that "contrary to rumor, the old drunk by the school bus is not a former teacher at Bullworth". The exact nature of the Hobo's relationship to the school and its staff is unknown, however.

The Hobo's last name is Grant. One of the townswomen has a line of dialogue that states about a Mr. Grant and the Korean War, and in fact the game's data files list his name as Mr. Grant. It is vaguely hinted by putting various lines of dialogue together that Mr. Hattrick was responsible for the friendly fire incident in Korea. Another reference to Mr. Grant is Miss Kopke saying that she heard "that Mr. Grant was once a star of the Scottish stage", an allusion to his voice actor's theater career. Moreover, Mihailovich claims that Mr. Grant may have been the mayor of Bullworth at some point.