<Tr> <Th> Created by </Th> <Td> Christopher Nolan David S. Goyer </Td> </Tr> <Tr> <Th> Portrayed by </Th> <Td> Heath Ledger </Td> </Tr> <P> The Joker is a fictional character who appears as the main antagonist in Christopher Nolan's 2008 superhero film The Dark Knight . Based upon the DC Comics character of the same name, he was played by late Australian actor Heath Ledger . A psychopathic mass murderer with a sadistic sense of humor, the Joker's arc follows his attempt to undermine the efforts of Batman (Christian Bale), James Gordon (Gary Oldman), and Harvey Dent (Aaron Eckhart) to rid Gotham City of crime . The character embodies themes of chaos, anarchy and obsession: throughout the film, he expresses a desire to upset social order through crime, and defines himself by his conflict with Batman . </P> <P> Ledger's interpretation of the character is specifically influenced by the graphic novels Batman: The Killing Joke and Arkham Asylum: A Serious House on Serious Earth . In the film, he wears the character's traditional color palette, while his facial appearance includes clown makeup that covers facial scars of a Glasgow smile . The character also explores techniques found in Ledger's previous performances, including his clown act in Terry Gilliam's fantasy film The Brothers Grimm . Further, it references paintings by artist Francis Bacon, Anthony Burgess' novel A Clockwork Orange and various punk rock musicians . Ledger's casting as the Joker was initially controversial, who seemed an unlikely choice for the role . </P>

Who gave voice to joker in dark knight