Batgirl first appeared in Batman #139 in 1961, over 20 years after the first appearance of Batman in Detective comics. The original Batgirl was Betty Kane, but she only lasted a few years and was replaced in 1964 by Barbara Gordon in Detective Comics #359. Barbara Gordon is the daughter of Commission Gordon, a long time ally in Batman’s fight against crime.
Interestingly, the character that eventually lead to Batgirl, first appeared in the mid 1950’s as a reaction to Fredric Wertham’s Seduction of the Innocent book that created a large “comic book panic” and accused Batman of being homosexual.
Batgirl (Kathy Kane) was brought in to be Batman’s love interest. A few years later, the original Batgirl (Betty Kane) was brought in as Batgirl’s niece and a love interest for robin.
The Barbara Gordon Batgirl became very popular, as did all things Batman, due to the Batman television series of the mid sixties. Batgirl was brought into the television series to help attract a female audience.
This popularity waned after the show was canceled, but the new Barbara Gordon batgirl continued to make sporadic appearances in the Batman line of comics from 1966 to 1988. The Batgirl character was changed from a teenager to an adult in the comic after the television show ended, but otherwise remained the same.
Batgirl “retired” in 1988 after being shot and paralyzed by Batman’s nemesis, the Joker. She reappeared soon after as the Oracle a computer wizard who helped various costumed crime fighters with her information gathering and computer hacking abilities.
A series of short term Batgirls appeared in the following years, but none long enough to hold the title.