Why does Barry Keoghan's Joker come adorned with so little of the character's trademark green hair in The Batman? Although technically not even credited in the finished movie, Joker has become one of The Batman's biggest talking points. Pre-release rumors claimed Eternals' Barry Keoghan had been cast as DC's latest cinematic Joker, but Matt Reeves set up decoy scenes of the actor in an entirely different role. Keoghan shows up in The Batman's ending as a shadowy Joker-like figure, but is credited only as "Unnamed Arkham Prisoner," leaving Reeves himself to confirm everyone's suspicions. The Batman's director also mentioned a longer Joker scene had been cut from the movie, and that deleted footage is now available online, revealing Keoghan-Joker in all his menacing glory.
The Batman's Clown Prince of Crime is quite unlike anything seen previously on the big screen - certainly in terms of his appearance. Keoghan's Joker was - according to Matt Reeves - born with a congenital disease that renders a permanent smile upon his face. That condition has resulted in considerable scarring, and the prosthetic effects lean more into horror territory than any movie Joker depiction prior. His familiar white make-up is barely visible across cracked, broken skin, and the iconic outfit is, of course, replaced by an Arkham jumpsuit.
Another major design difference in Barry Keoghan's Joker is the hairstyle... or lack thereof. A luscious head of green hair is usually one of Joker's defining traits, but The Batman's deleted scene reveals Keoghan's head covered in only small green tufts sporadically dotted across his scalp. A view from behind even shows Joker verging on the edge of baldness. The Batman hasn't provided enough details for fans to be sure of the reason behind Joker's hair loss, but there are enough clues to make an educated assumption... and it's possible Joker might've done this to himself.
Matt Reeves (via IGN) described The Batman's Joker as suffering a lifelong medical condition that pulls his face into a constant smile. Close-ups of the villain's mouth in deleted footage show this disease has left scars across his mouth and cheeks, perhaps due to the permanent strain of endless grinning. However, a far larger scar runs all the way down the back of Joker's head, crudely attached with what appear to be staples. This wound evokes DC comics' "Death of the Family," in which Joker removed and reattached his own face. Since Matt Reeves has already discussed Joker's "dark" reaction to having a congenital disease, The Batman's version might've attempted surgery on himself. Any potential removal/fiddling with the location of one's face would inevitably damage hair follicles, which could explain Joker's patchy hairstyle in The Batman's deleted scene.
Whatever the reason for Joker's relative lack of hirsuteness compared to past incarnations (Cameron Monaghan's Gotham incarnation aside), the strange quality certainly compliments Barry Keoghan's striking character design. Random spurts of hair rather than a full spread - especially if self-inflicted - very much reflects Joker's mentality in The Batman. We know Keoghan isn't quite Joker yet, but rather a proto version who will one day embrace that title and persona wholly. These small, green shoots emanating from Joker's head - as opposed to the famous green hair DC fans are accustomed to - represent how the villain is still developing his super-criminal alter-ego, similar to how Batman's Batmobile is still essentially just a car, and Selina Kyle isn't yet known as Catwoman at this early point in his timeline.
