All of Rowling's novels feature huge casts of characters, far too many to enumerate in this space. Selected brief character profiles follow, highlighting the major players in the first volume.
Harry Potter: The eleven-year-old, orphaned boy who discovers that he is a wizard. Harry is famous in the wizards' world because, as a baby, he survived an attack from the evil Lord Voldemort. He is known as "the boy who lived," and his survival put an end to Voldemort's power for many years. Readers are introduced to and experience the wizards' world that exists alongside our own through Harry's eyes. More than simply the protagonist of this novel and those that follow it, Harry is truly the "hero" of the story in the classic, mythic sense.
The Dursleys: Uncle Vernon, Aunt Petunia, and Dudley, who live boorish, self-centered, and exceptionally dull lives at Number Four, Privet Drive, and who represent all that is worst about the "Muggle" (non-magical) world; chiefly, its cardinal sin of a lack of imagination and a refusal to be open to new, extraordinary possibilities.
Rubeus Hagrid: The giant who serves as gamekeeper at Hogwarts School of Witchcraft and Wizardry, and who has a fondness for all magical creatures, especially dragons.
Albus Dumbledore: The headmaster at Hogwarts School, a great wizard and a seemingly omniscient character, and also very nearly omnipresent. In this and the other novels, he can be counted upon to show up not when circumstances are at their worst, but immediately thereafter. As Rowling's plots make clear, Harry-again, the classic, mythic hero-must face the darkest circumstances on his own in order to achieve his quest for identity.
Minerva McGonagall: Deputy Headmistress and professor at Hogwarts School, who also serves as head of Gryffindor House, the community of students (one of four, the others being Hufflepuff, Ravenclaw, and Slytherin) with whom Harry resides and studies. She has the ability to transform herself into a cat.
Ron Weasley: One of Harry's two closest friends at Hogwarts, a first-year student like himself. Ron hails from a family of relatively modest means, and his family's social status makes Ron highly self-conscious. He must also deal with the fact that he follows his older brothers to Hogwarts, and must cope with the expectations that fact brings. (His sister Ginny will also attend Hogwarts beginning in the second novel, The Chamber of Secrets.) He is loyal and resourceful, as his behavior in the live game of wizard chess at the novel's close demonstrates. Ron's father works for the Ministry of Magic, whose function is to keep the magic world separate and secret from the Muggle world.
Hermione Granger: The other of Harry's two closest friends at Hogwarts. Hermione comes from a non-magical family, but she is able to quickly learn about wizards' ways thanks to her natural intelligence and her hard work. As her ability to figure out the potions puzzle in the dungeons illustrates, Hermione possesses logic-a quality which (according to her, at any rate) many wizards lack!
Neville Longbottom: One of Harry's fellow students and friends who seems inconsequential throughout most of the book, present seemingly only for comic relief. Yet his courage in standing up to his friends near the book's end, trying to convince them from pursuing the Sorcerer's Stone because he believes it to be dangerous (which it is, however justified a quest it might be) earns Gryffindor House the final points they need to win the House Cup for the year. In this sense, Neville may serve as a foil to Harry. Just as Harry is considered inconsequential in the Muggle world and turns out to be important, so is Neville considered inconsequential in the wizard world and turns out to be important.
Draco Malfoy: The son of a highly influential wizard, and the product of an old and established wizarding family, Draco will be Harry's nemesis throughout their years together at Hogwarts. Dumbledore tells Harry that his (that is, Harry's) relationship with Malfoy resembles the relationship which Harry's father, James Potter, had with Severus Snape when those two were fellow students at Hogwarts years before. Draco exhibits great animosity and prejudice toward those he considers his inferiors, such as students from non-magical families.
Severus Snape: The potions master at Hogwarts, who takes an immediate disliking to Harry (and vice versa) because of his old animosity toward Harry's father, James-who, years before, saved Snape's life. (The details of this event, however, are not narrated in this book.) Dumbledore speculates that Snape works so hard to protect Harry (albeit without Harry's knowledge) so as not to be in James Potter's debt any longer.
Professor Quirrell: The first of what will prove to be a long succession of Defense Against the Dark Arts professors in the Rowling novels. Quirrell turns out to be the servant of the evil Lord Voldemort, who is allowing the defeated Dark Wizard to use his body as he (Voldemort) plots a return to power.
Voldemort: Often referred to by fearful wizards as "He Who Must Not Be Named" or simply "You Know Who," Voldemort is the evil wizard whose power was broken when he murdered Harry's parents and tried-but failed-to murder Harry as well, when Harry was just an infant. Voldemort was not entirely defeated, however, and he has been slowly regaining his power in order to make a full return and dominate the wizard world-and perhaps the Muggle world as well-once and for all.