Harry first appears in "Harry Potter and the Philosopher's Stone" (published in the United States as "Harry Potter and the Sorcerer's Stone") as the book's protagonist, or main character. When Harry was a little over one year old, his parents were killed by the powerful Dark Wizard, Lord Voldemort. Harry survived Voldemort's Killing Curse after his mother died to protect him. The Curse was turned back at Voldemort and ripped his soul from his body. Because of this, Harry has a lightning-bolt shaped scar on his forehead. Rowling has said that creating the story about Harry Potter's past was a matter of reverse planning: "The basic idea [is that] Harry … didn't know he was a wizard … and so then I kind of worked backwards from that position to find out how that could be, that he wouldn't know what he was… When he was one-year-old, the most evil wizard in hundreds of years attempted to kill him. He killed Harry's parents, and then he tried to kill Harry - he tried to curse him… Harry has to find out, before we find out. And - so - but for some mysterious reason, the curse didn't work on Harry. So he's left with this lightning-bolt shaped scar on his forehead, and the curse rebounded upon the evil wizard who has been in hiding ever since".
Harry is written as an orphan living unhappily with his only family left, the cruel Dursleys. On his eleventh birthday, Harry finds that he is a wizard when Rubeus Hagrid tells him that he is to go Hogwarts School of Witchcraft and Wizardry. There he learns about his parents and his connection to the Dark Lord. He is "sorted" into Gryffindor House by the Sorting Hat and becomes friends with classmates Ron Weasley and Hermione Granger. Near the end of his first year at Hogwarts, he stops Voldemort's attempt to steal the Philosopher's Stone via Quirinus Quirrell. He also forms rivalries with characters Draco Malfoy, a classmate from an elitist wizard family, and the Potions teacher and head of Slytherin House, Severus Snape. Both feuds continue throughout the series. In a 1999 interview, Rowling stated that Draco is based on several schoolyard bullies she had known and Snape on a teacher of hers who abused his power.
Rowling has said that the "Mirror of Erised" chapter in "Harry Potter and the Philosopher's Stone" is her favourite. The mirror reflects Harry's deepest desire, namely to see his dead parents. Her favourite funny scene is when Harry accidentally sets a boa constrictor free from the zoo in the horrified Dursleys' presence.
In the second book, "Harry Potter and the Chamber of Secrets", Rowling pits Harry against Tom Marvolo Riddle, a memory of Lord Voldemort locked up in a secret diary that Ron's younger sister Ginny Weasley finds in a bathroom. When Muggle (non-magic) parentage students are found being petrified, many think that Harry may be the one behind the attacks, making him become more detached from his classmates. At the height of the book, Ginny Weasley is found to be missing. To rescue her, Harry battles Riddle and the monster he controls that is hidden in the Chamber of Secrets.
In the third book, called "Harry Potter and the Prisoner of Azkaban", Rowling uses time travel as the basis for the book. Harry learns that his parents were sold out to Lord Voldemort by their friend Peter Pettigrew, also accused of framing Harry's godfather Sirius Black for crimes he didn't make, locking him up in the wizarding prison, Azkaban. When Black escapes to find revenge, Harry and Hermione use a Time Turner to save him and a hippogriff named Buckbeak. Pettigrew, and the truth, escape from Sirius, causing him to be on the run from the authorities.
In the previous books, Harry is written as a child, but Rowling states that in the fourth novel, "Harry Potter and the Goblet of Fire", "Harry's horizons are literally and metaphorically widening as he grows older." Harry's developing maturity becomes apparent when he becomes interested in Cho Chang, a pretty Ravenclaw student. Tension mounts, however, when Harry is mysteriously chosen by the Goblet of Fire to compete in the dangerous Triwizard Tournament, even though another Hogwarts champion, Cedric Diggory, was already selected. It is actually an elaborate scheme by Lord Voldemort to lure Harry into a deadly trap. During the Tournament's final challenge, Harry and Cedric are teleported to a graveyard. Cedric is killed, and Lord Voldemort, aided by Peter Pettigrew, uses Harry's blood in a gruesome ritual to resurrect Voldemort's body. When Harry duels Voldemort, their wands' magical streams connect, forcing the spirit echoes of Voldemort's victims, including Cedric and James and Lily Potter, to be expelled from his wand through Priori Incancatem. The spirits shortly protect Harry as he escapes to Hogwarts with Cedric's body. For Rowling, this scene is important because it shows how Harry is brave, and by finding Cedric's corpse, he demonstrates selflessness and compassion. Says Rowling, "He wants to save Cedric's parents additional pain". She added that preventing Cedric Diggory's body from falling into Voldemort's hands is based on the classic scene in the "Iliad" where Achilles finds the body of his best friend Patroclus from the hands of Hector. The author said: "That [Iliad scene] really, really, REALLY moved me when I read that when I was 19. The idea of the desecration of a body, a very ancient idea... I was thinking of that when Harry saved Cedric's body." She also said that she cried while writing the scene when Harry's dead parents are drawn from Voldemort's wand, the first time she cried while penning her story.
In the fifth book, "Harry Potter and the Order of the Phoenix", the Ministry of Magic has been waging a smear campaign against Harry and Dumbledore, disputing their claims that Voldemort has returned. A new character is introduced when the Ministry of Magic appoints Dolores Umbridge as the latest Hogwarts' Defence Against the Dark Arts instructor (and Ministry spy). Because the paranoid Ministry thinks that Dumbledore is building a wizard army to overthrow them, Umbridge decides not to teach students real defensive magic. She gradually gains more power, eventually seizing control of the school. As a result, Harry's growing angry and erratic behaviour nearly estranges him from Ron and Hermione. Rowling says she put Harry through extreme emotional stress to show his emotional vulnerability and humanity–a contrast to his nemesis, Voldemort. "[Harry is] a very "human" hero, and this is, obviously, a contrast, between him, as a very human hero, and Voldemort, who has deliberately "de"humanised himself. And Harry, therefore, did have to reach a point where he did almost break down, and say he "didn’t" want to play anymore, he "didn’t" want to be the hero anymore – and he’d lost too much. And he didn’t want to lose anything else. So that – "Phoenix" was the point at which I decided he would have his breakdown." At Hermione's urging, Harry secretly teaches his classmates real defensive magic to thwart Umbridge and the Ministry, but their meetings are found and Dumbledore is ousted as Headmaster. Harry suffers another emotional blow, when his godfather, Sirius Black is killed during a battle with Death Eaters at the Department of Mysteries, but Harry ultimately defeats Voldemort's plan to steal an important prophecy and helps uncover Umbridge's sinister motives. Rowling stated: "And now he [Harry] will rise from the ashes strengthened." A sideplot of "Order of the Phoenix" involves Harry's romance with Cho Chang, but the relationship quickly unravels. Says Rowling: "They were never going to be happy, it was better that it ended early!"