Argus Finch

David Bradley plays the role of Argus Filch, the eerie squib and caretaker of Hogwarts. Argus used to wander around the campus creepily with his cat, Mrs. Norris, eager to catch any student who might be breaking the rules.

Source: Zen Herald

David Bradley has played a lot of interesting roles after the Harry Potter franchise. He appeared in Captain America: The First Avenger. You can also see him in Game of Thrones as Walder Frey. He has done a lot of voice-acting jobs as well.