Daniel Radcliffe as Harry Potter, the protagonist. He has to battle with much of the Wizarding world's denial over Harry's encounter with the evil Lord Voldemort at the end of the previous year. He teaches his friends to defend themselves in duels.
Ralph Fiennes as Lord Voldemort, the antagonist, who lures Harry to the Ministry of Magic and nearly kills him.
Michael Gambon as Albus Dumbledore, the Hogwarts headmaster. He upsets Harry by remaining distant from him throughout the year, but explains at the end of the film why he isolated himself. He also explains the meaning of the prophecy to Harry.
Gary Oldman as Sirius Black, Harry's godfather who, during the battle at the Department of Mysteries, is killed by his cousin Bellatrix Lestrange, causing Harry great emotional damage.
Alan Rickman as Severus Snape, the Potions master. He helps teach Harry to block his mind's connection to Lord Voldemort's. He holds a grudge against Harry because he and Harry's father hated each other while they were at school together.
Mark Williams as Arthur Weasley, Ron's father who acts as a paternal figure to Harry. Harry saves him from death when he sees a vision of Arthur being attacked.
Robert Hardy as Cornelius Fudge, the Minister of Magic who refuses to believe that Lord Voldemort has returned.
