Summer Hathaway is a main character and the band manager of the band. Summer is usually strict and mischievous and is very clever for her age.
Summer is the class factotum. She played the clarinet in the school music class, and becomes the manager of Dewey's School of Rock band. Summer is well-educated, clever, responsible but sometimes sarcastic young girl. As the class factotum, she thinks mostly of succeeding and earning good grades.
When Dewey gave her a role as the band's "groupie", she looked up the term and was displeased that she was to be what she compared to a slut. She threatened to tell her mother about her part in the "class project", and Dewey was forced to give her a more important role as the band's manager, which she accepts and takes seriously. Oddly, despite being smart and clever, she was easily tricked by Dewey to believe that they would be graded for the "class project".