The Joker is a fictional character who appears in Christopher Nolan's 2008 superhero film The Dark Knight, based upon the DC Comics character and supervillain of the same name. He was portrayed by Heath Ledger. A psychopathic criminal mastermind and mass murderer with a warped, sadistic sense of humor, the Joker is hired by Gotham City's mob bosses to kill the vigilante Batman (Christian Bale), and also comes into conflict with Batman's allies, Gotham police officer James Gordon (Gary Oldman) and district attorney Harvey Dent (Aaron Eckhart). The Joker embodies themes of chaos, anarchy and obsession: throughout the film, he expresses a desire to upset the social order in Gotham through crime, and defines himself by his conflict with Batman.