Joe Chill was a homeless man living in Gotham, who turned to crime to his poverty. Like many others left homeless by the wealth divide, he was desperate and would rob people for money in the alleys of Gotham. One night he tried to mug Thomas and Martha Wayne, who were leaving the opera. However the robbery went wrong and he ended up shooting and killing both of them, leaving their orphaned son Bruce alone with their bodies. Chill was soon arrested by the GCPD and jailed.
In jail, he shared a cell with mob boss Carmine Falcone and learned incriminating evidence about the man. After Falcone was released, Chill arranged with the lawyer Carl Finch that he would get an early release in exchange for testifying against Falcone. At the hearing, Chill saw Bruce Wayne in the crowd. As he left the courthouse, an assassin sent by Falcone shot Chill and killed him, in order to keep him from testifying.