Actor Ian Hart made his first and only appearance in the Harry Potter film franchise as Professor Quirinus Quirrell. In Harry Potter and the Sorcerer's Stone (2000) Quirrell is one of many wizards in a pub who greets Hagrid accompanied by the boy who lived. By our first impression, Quirrell looks harmless. He's wracked with nerves, a verbal stutter, and jumps at the slightest unexpected sound.
Perhaps our most memorable moment of his character is when the troll has escaped the Hogwarts' dungeon. Fleeing into the Great Hall where the students and professors are gathering for a feast, Quirrell exclaims "Troll in the dungeon! Thought you oughta know" and promptly faints.
We come to find out during the finale of the book and film that Quirrell has been the possessee of Lord Voldemort. By using Quirrell' spirit, the dark lord has returned to Hogwarts to annihilate young Mr. Potter. But the young Gryffindor's power of love defeats them both, and Quirrell is reduced to ash.
So where has Ian Hart, the actor who portrayed Professor Quirrell, been? Since co-starring in the first film of the franchise Hart has starred in a variety of television shows, films, and theater. You may have seen him as Sir Arthur Conan Doyle in Finding Neverland (2004) starring Johnny Depp and Kate Winslet and as Adolf Hitler in The Man Who Crossed Hitler. Most recently he made an appearance on the U.S. Television show Bates Motel (2013).