The Batman villain voiced by Zach Galifianakis in The Lego Batman Movie is The Joker.
Galifianakis gives the film’s Joker a comic, theatrical personality while retaining the character’s central role as Batman’s arch-enemy. In the story, Joker wants Batman to admit that he is his greatest enemy, turning their familiar rivalry into the film’s main emotional conflict.
The casting connected Galifianakis with Will Arnett, who voices Batman. Their performances make the rivalry deliberately playful and self-aware, reflecting the film’s broader habit of joking about Batman’s history across comics, television, and earlier movies.
A common mix-up is confusing this role with other Lego adaptations. The Joker has been voiced by several actors in different games and animated projects, including Mark Hamill in other Batman productions, but Galifianakis specifically voices him in the 2017 film.