Garry Ball is a student at William Penn who is friends with Adam.
Garry is described as a "cool kid" by Adam. That hints that he has a lot of friends. He is also friends with Adam, Dave Sirota, Chad Kremp, and Dave Kim.
In the episode "I Drank The Mold", it is revealed that Garry has a mother whose name is unknown, and his father is Earl Ball, principal of William Penn. It is unknown whether or not Garry has any siblings.