Leonardo DiCaprio and Joaquin Phoenix Were Offered the Role of the Joker in The Dark Knight, But Turned it Down Leonardo DiCaprio and Joaquin Phoenix were both offered the role of Joker in The Dark Knight, but ended up turning it down, according to the film's casting director. Read the full story at IGN: https://www.ign.com/articles/leonardo-dicaprio-and-joaquin-phoenix-were-offered-the-role-of-the-joker-in-the-dark-knight-but-turned-it-down