Who is headmaster of hogwarts in Harry Potter and the Deathly Hallows how?

In *Harry Potter and the Deathly Hallows*, the headmaster of Hogwarts is Minerva McGonagall.

This is after the death of Albus Dumbledore in the previous book, *Harry Potter and the Half-Blood Prince*. McGonagall takes on the role of Headmistress and becomes a key figure in the resistance against Voldemort.