Kathy Kane was a circus trapeze artist who wanted more in life. Admiring the Batman, she used her fortune to get the supplies she needed (like Batman) to become Batwoman and fight crime.

Over the years, Batman often tried to convince Kathy to retire, implying that fighting crime was no place for a woman, but Kathy finally convinced Batman of her worth as a crime-fighter and often teamed up with Batman and Robin Kathy later did retire from crime-fighting and bought a circus, Kane's Kolossal Karnival, although she did occasionally still fight crime if needed, even teaming up with the Batgirl, Barbara Gordon, on several occasions.

Following a tip that the League of Assassins was going after Kathy Kane at her circus, Batman showed up just as she was attacked by the League, and Batman was knocked unconscious by the Bronze Tiger, who at that time was in the thrall of the Sensei, leader of the League of Assassins. He awakened to Kathy's scream and found her dead, murdered by two members of the League.  Batman later tracked the killers to the the Sensei's lair and fought the Bronze Tiger and several of the league members.  The Sensei and the Bronze Tiger escaped, but Batman captured Kathy Kane's two killers, avenging her death.

Although it is unknown whether Batwoman actually ever existed or if she was erased during the Crisis on Infinate Earths, while Batman was investigating a disturbance at the Planet Krypton restaurant, he met the Batwoman "ghost" and somehow recognized her as "Kathy", who was a ghost who (because of Hypertime) could have existed in thousands of different realities.