Hermione Jean Granger was a Muggle-born witch born to Mr and Mrs Granger, both dentists. Hermione was raised as a Muggle girl until, at age eleven, when she learned that she was a witch and had been accepted into Hogwarts School of Witchcraft and Wizardry. She began attending the school on 1 September, 1991, where she was subsequently sorted into Gryffindor House, despite being considered for Ravenclaw. She possessed a brilliant academic mind, and proved to be a gifted student in almost every subject that she studied. She was very studious and bookish.

Hermione first met Harry Potter and Ron Weasley aboard the Hogwarts Express. Both boys found Hermione unfriendly and somewhat of an insufferable know-it-all. Later, her eagerness to please her professors and her constant correct answers reinforced their initial impression. However, in spite of the cool relationship between the three, Hermione stepped in to take the blame from Ron and Harry after they had saved her from a troll on Hallowe'en . Harry and Ron were surprised, but grateful and the three quickly became friends.