What makes Harry Potter a famous wizard at Hogwarts School of Witchcraft and Wizardry in Harry Potter and the Sorcerer's Stone?

Harry James Potter became a household name in the wizarding world when he was just a baby. He is the only known person to have survived the Killing Curse. Harry was 15 months old when Voldemort attempted to murder him. For reasons no one can explain, Harry was left with a lightning bolt scar on his forehead, and Voldemort had seemingly been defeated. For the first 11 years of his life, Harry was raised in the muggle world, completely unaware of his fame.
Harry arrives at Hogwarts, where everyone knows him as The Boy Who Lived—the wizard who, as a baby, unbelievably and mysteriously defeated a powerful dark wizard. Harry has been the subject of attention and speculation in the wizarding world for nearly all of his life. The Dursleys had attempted to suppress Harry's wizardry, and he grew up completely unaware of the fame that hovers around him among the students at Hogwarts.
Harry's fame grows throughout his first year at Hogwarts. He becomes Hogwarts's youngest seeker in a century. When Professor Quirrell unleashes a troll in the dungeons as a distraction in an attempt to steal the stone, Harry and Ron save Hermione from a troll, although they have very little experience with magic. At the end of the novel, Harry, Ron, and Hermione succeed in passing all the teachers' defenses that guard the stone, with Harry preventing Voldemort's return. In the infirmary, Harry learns that the entire school has learned of what himself and his friends achieved.