Arnold Stromwell was a prominent mob boss in Gotham City. Even as a young boy Arnold Stromwell would steal much to his brother Michaels disapproval. Once while playing by some train tracks Michael saved Arnold from getting run over by a train. Michael however lost his leg while doing this. When Arnold became an adult he he was a leading crime figure in Gotham City until the arrival of Rupert Thorne. Stromwell is also the uncle of Tony Zucco, the man who killed Dick Grayson's parents. After Zucco killed the Flying Graysons, Batman went to Stromwell's house to question him. Stromwell lied and told Batman that he didn't know where Zucco was. Years later the mob war between Stromwell and Thorne intensified. Thorne even tried to kill Stromwell but he was saved by Batman. The Dark Knight then took Stromwell to the Sunrise Foundation, a drug rehabilitation center. When Stromwell went inside he saw his son Joey laying on a hospital bed being treated for grug overdose. Stromwell then realized it was the drugs that he manufactured that his son got hooked on. Batman then saved Arnold and Michael from Rupert Thorne. After this Stromwell decided to stop his life of crime and gave the police all his information on the gangs in Gotham City.