Webb has had supporting roles in Harry Potter and the Prisoner of Azkaban (2005), The Dark Knight (2008) from the Batman franchise, Robin Hood (2010), and Pirates of the Caribbean: On Stranger Tides (2011). In roles with more visibility, he has played Emilio, a kidnapper in The Lives of the Saints (2006), and Tony the sidekick in Pusher (2012). Webb also plays Will, a central character in "Winter Is Coming", the first episode of HBO's Game of Thrones.