Albus Dumbledore is the headmaster of Hogwarts when Harry Potter first arrives in J.K. Rowling’s series.
Dumbledore is introduced in Harry Potter and the Philosopher’s Stone as the respected headmaster of Hogwarts School of Witchcraft and Wizardry. He is portrayed as a powerful wizard, a mentor to Harry, and a leading opponent of Lord Voldemort.
Minerva McGonagall is deputy headmistress when Harry begins school, which can cause confusion. Severus Snape teaches at Hogwarts and later becomes headmaster for a period, while Armando Dippet held the role in an earlier era shown through the books’ history.
Dumbledore remains headmaster through most of Harry’s school years, although the position changes temporarily during the series. His connection with Harry includes both guidance and carefully withheld information about the wider conflict.