Which Hogwarts headmaster is killed by Severus Snape in J.K. Rowling’s Harry Potter series?

Albus Dumbledore is the Hogwarts headmaster killed by Severus Snape in J.K. Rowling’s Harry Potter series. The killing occurs at the end of Harry Potter and the Half-Blood Prince.

Dumbledore is struck by Snape’s Killing Curse on the Astronomy Tower after Draco Malfoy is unable to carry out Voldemort’s order. The scene initially appears to show betrayal, but later revelations explain that Dumbledore and Snape had arranged the act as part of a larger plan.

Dumbledore had been weakened by retrieving and destroying a Horcrux-linked object, and he knew that his death was approaching. Snape’s actions allow him to maintain his position close to Voldemort while helping protect Draco. The circumstances are clarified fully in Harry Potter and the Deathly Hallows.