A Sergeant in the Gotham City Police Department, Pettit led the SWAT team and was always more than happy to go into action, displaying a willingness to storm into situations rather than try any diplomatic solutions. Nonetheless, he was very good at his job and survived several years in a city notorious for its many dangerous costumed criminals. When the city was cut off from the rest of the USA and declared a 'No Man's Land', Pettit was one of the many police officers who remained behind, but he soon became dissatisfied with James Gordon's leadership, frequently criticising him for not taking a stronger stance on issues and for being afraid to deal strongly with their enemies. Eventually, he led a rival faction of former police officers who were prepared to do whatever it took to survive, and allied himself with the Huntress.
However, the pressures of the situation got to him and he became increasingly dictatorial to the point where he was practically indistinguishable from any of the crime lords who controlled areas of Gotham. In a confrontation with the Joker, it became clear that he was no longer capable of command and had become extraordinarily dangerous himself. Some of his men were captured and dressed to look like the Joker, he shot each and every one of them as they appeared, without seeming to care at all. When Foley left to get help from the other police faction, Pettit shot and killed him, too, as he had not been granted permission to leave. Huntress tried to get him to see sense, but even as she tried in vain, Pettit was himself killed by the Joker.
When Harley Quinn died and was sent to Hell, it was revealed that Pettit had managed to raise himself in status from that of a mere tortured soul to that of a tormentor. Now a demonic detective in charge of Hell's version of the GCPD SWAT team, his job was to prevent Harley and her Quinntets from surviving a stand-off, which would repeat itself for all eternity. Despite the apparent hopelessness of the situation, Harley refused to remain in Hell and so relentlessly tried to escape. Pettit frequently managed to kill her, causing the stand-off to reset itself, but eventually Harley nearly made it out of Hell, only to be killed by the demonic-enforcer, Ulysses Highwater. Once again sent back to Pettit, he attempted to break her spirit to prevent her constant escape attempts, but eventually Harley managed to make Pettit doubt his worth in Hell, and she made a deal with him that she guaranteed would keep him safely in his position. The deal ended up being a double-cross, and Harley escaped Pettit's custody, leaving him humiliated and busted back down to tortured soul at the bottom of the pits of Hell, a fate that a former subordinate stated was something you could never come back up from, and was "Just what he deserves."