Two actors who previously played Batman have made appearances on the show: Adam West and Kevin Conroy. Adam West played Mayor Grange and Kevin Conroy played John Grayson.
In terms of overall tone and style, the series is based principally on the original stories from the early Batman comics from the Golden Age until the late 1960's.
The show's creative team were cleared to use all Batman-related characters besides Scarecrow, Ra's al Ghul, and Two-Face because of their planned use in Christopher Nolan's live-action movie Batman Begins (2005). With various projects featuring Batman in production, DC Comics president Paul Levitz had decided to implement an industry wide decision to restrict Batman-related characters exclusive to certain shows across the television and film medium to avoid brand confusion. Fans referred to this restrictive practice as the "Bat-Embargo". Batman himself was allowed to appear in multiple projects, but DC had decided to divide up the Batman-related characters were divided up as follows: "Batman Begins" got first priority to any Batman-related characters the filmmakers wanted to use for their project, next this show was allowed to feature all of the other popular and more well-known Batman-related characters that the "Batman Begins" filmmakers didn't need for their project, and finally for Justice League Unlimited (2004) the show's creative team were told starting with the episode Double Date (2005) that they would be restricted from using all Batman-related characters besides Batman himself and a few lesser-known Batman villains who didn't appear on Batman (1992) and Batman (1997). That JLU episode seems to be the catalyst that put the Bat Embargo in effect since it was originally going to be a Birds of Prey tribute and going to feature Barbara Gordon/Batgirl as one of the prominent characters, but plans were made for the character to appear on this series for the third season in 2005 since Kids WB demanded a sidekick for Batman in this show and the rights to Robin were tied up with Les Jeunes Titans (2003). The Bat Embargo wouldn't affect JLU too much since it's a Justice League show with a vast majority of the DC Comics characters available to be featured in it after DC had bent over backwards to allow as many characters to be used. Harvey Dent/Two-Face ultimately didn't appear in "Batman Begins" but was saved for the sequel The Dark Knight : Le Chevalier noir (2008).
The Edge (Dave Evans) from U2 performed the opening theme. Season three featured a new opening theme that was a cross between the Neal Hefti themes from Batman (1966) and Hawaii police d'état (1968). Back in 1995, he and his fellow U2 band mates played a song for the Batman Forever (1995) soundtrack called "Hold Me, Thrill Me, Kiss Me, Kill Me".
The character of Ellen Yin is a direct reference to the character Ellen Yindel in Frank Miller's famous "Batman: The Dark Knight Returns" graphic novel.