Tim Curry was initially cast as the Joker, having also been considered for the role in Batman (1989), and it was long rumored that his portrayal was deemed "too scary." In reality, Curry had recorded four episodes, but dropped out after developing Bronchitis. The role went to Mark Hamill, who had already been cast as one-off character Ferris Boyle in Heart of Ice (1992). Curry ended up providing additional voices in a handful of episodes. His audio as the Joker finally surfaced in 2022.
When establishing Two-Face, the writers took the time to first show his alter-ego, Harvey Dent, in several episodes, so the audience could get to know him better. That way, they were more shocked at his transformation from the upstanding Dent to the monstrous Two-Face. The writers believed this made him into one of the show's best characters, and his origin is considered one of the show's best episodes.
All voice acting was, unlike most voice-over work, performed ensemble. This means that all of the voice actors performed their lines in a room together, rather than at separate times in different locations. Mark Hamill was the only cast member allowed to perform his Joker voice while standing, to make it easier to infuse the character with the manic energy the role required. All of the other actors recorded their lines while sitting.
The title of the show is never seen. The producers decided that since Batman was an instantly recognizable character that anyone in any language would be able to tell what the show was about.
Kevin Conroy is the first person in animation to use two distinct voices to portray Bruce Wayne and Batman, inspired by Michael Keaton's performance in Batman (1989), the first to do so.