Draco Malfoy
Herdman started acting when he was about 7 years old; his father found him an agent. At age 13, he was cast as Gregory Goyle, a sidekick of villain Draco Malfoy, in "Harry Potter and the Philosopher's Stone" (2001). Over the next decade, he returned as Goyle in all seven sequels. He was originally considered for the role of Dudley Dursley, Harry's spoiled cousin, but it went to Harry Melling.