Interesting that they've brought back a character that originated in the films for a different iteration. Apart from Harley Quinn and Renee Monyoya, who originated in the animated series, I don't believe any live-action show or film has done this before (replacing Katie Holmes with Maggie Gyllenhaal within the *same* canon, doesn't count).
I guess you could kinda say Batgirl, who was created for the 1966 Batman TV show. She later appeared in Schumacher's Batman & Robin (although a different version), the live-action Birds of Prey TV show (only in flashbacks, I believe), and the recent (never to be released) Batgirl movie.
Was Batgirl specifically created for the TV show? I know she only appeared in the third season, and prior to her appearance there was a female bat-orientated character in the comics from 1961 called 'Bat-girl'.
You could be right, but I just wanted to be sure, because I always that she was adapted from the comics for the small-screen.
Yes, the producers of the TV show wanted a female hero to help out Batman and Robin in the third/final season, so they asked DC to create one. DC came up with Barbara Gordon/Batgirl. The producers were happy and committed to the character. Then they asked DC to introduce her in a comic shortly before her first appearance on the show as advance marketing.