Scarecrow, Ra's al Ghul, and Two-Face were restricted from appearing on this series, because of their planned use in Christopher Nolan's live-action The Dark Knight movie trilogy. Scarecrow and Ra's al Ghul appeared in Batman Begins (2005) and The Dark Knight Rises (2012), and Two-Face appeared in The Dark Knight (2008) (which also prominently features The Joker, but since he is Batman's greatest enemy, he was allowed to appear on the series). Bane and Catwoman were never restricted, because development for The Dark Knight Rises (2012) did not take place until this series ended.
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.
Kevin Michael Richardson became the first, and so far only, African-American actor to play The Joker.
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.
For Robin's costume, Jeff Matsuda said he used the Tim Drake Robin costume from the comics as a starting point, and took out what he didn't like. Some of the changes were, bringing back the traditional pixie shoes, making the "R" symbol a yellow circle with a black "R" (like it was in The New Adventures of Batman (1977)), and giving Robin a modern version of the Dick Sprang styled hair from the comics.
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 Five-O (1968). Back in 1995, he and his fellow U2 band mates played a song for the Batman Forever soundtrack called "Hold Me, Thrill Me, Kiss Me, Kill Me".
This is the first Batman cartoon to introduce Batgirl before Robin. Batgirl was introduced before Robin simply because Robin was still being used on Teen Titans (2003), which had been renewed for a fifth season, which aired on a different network. Robin in this show looks exactly like he did on Teen Titans (2003), albeit a few years younger. He also uses Bird-A-Rangs and uses a bow staff as a weapon, just as he did on Teen Titans (2003).
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.
Batman's cowl featured shorter ears, because it was more boxer-like, according to Jeff Matsuda, and the nose is flatter than previous versions. This show's Batman design took inspiration from Jim Lee's artwork from the "Batman: Hush" storyline from the comics. Though the series is based on the early comics by Bob Kane and Bill Finger, the Jim Lee look was used, since it was a fresher, more modern look, and the original long ears and black bat chest emblem look, was already being used by Batman in the unrelated Justice League Unlimited (2004) animated series. In season four, Batman's chin was redesigned to be more square, and less pointy.
This was the first Batman animated series to feature Professor Hugo Strange in multiple episodes. The character has never appeared in more than one episode in any previous Batman, or DC animated series. Strange is one of Batman's first recurring villains, preceding The Joker and Catwoman in the comics by several months.
Besides his standard Batman suit, many other suits - including a Rocket Shield suit, an Anti-Freeze suit, a Bat-A-Wing suit, and a Bat-Bot suit - were designed by Mattel to be used on the show and to sell action figures.
One of the villains who made his debut in the series was The Ragdoll. The Ragdoll is actually an old foe of the Golden Age Flash, not the Batman, as the episode claims.
As with previous Batman animated shows, a past Batman stars as a character in the new show, Adam West in Batman: The Animated Series: Beware the Gray Ghost (1992), and hands off the Batman mantle to Kevin Conroy. In The Batman (2004), Kevin Conroy plays Dick Grayson's father, in a way, handing the Batman torch to Rino Romano.
The name of reporter "Robinson Sprang" is taken from artists Jerry Robinson and Dick Sprang, both of whom drew Batman in the 1950s.