- "I don't 'try' and I never stop. You won't see me coming and you won't feel a thing."
- —Victor Zsasz to James Gordon[src]
Hitman for Falcone
Victor Zsasz is sent by Carmine Falcone to the Gotham City Police Department to collect Jim Gordon. Two women in black leather accompany him. When Jim refuses to go, Zsasz demonstrates the power and fear he commands by ordering the police officers to leave. He then attempts to assassinate Gordon. However, after a pitched firefight, a wounded Jim escapes when Renee Montoya and Crispus Allen arrive on the scene. Victor Zsasz then kills a female police officer that he had shot during the firefight, and marks it on his arm as his 28th kill. Later on, he is seen keeping an eye on Barbara Kean (who had attempted to negotiate with Falcone to drop his hit on Gordon) at the time when Jim Gordon and Harvey Bullock arrived to bring in Falcone, after picking up Mayor Aubrey James. Gordon and Bullock drop their plans in exchange for Falcone having Zsasz release Barbara. 
Zsasz provides the pep talk that turns Don Falcone's thinking around when the mob boss is planning to give in to Fish Mooney's coercion. Zsasz is later seen discussing with Falcone about Fish Mooney's ploy, Liza who he then finds out was sent in by Mooney. Zsasz then accompanies Falcone when he kills Liza and overthrows Mooney's club.
After Fish Mooney and Butch Gilzean return to the club, finding Oswald Cobblepot trying himself as the head of the club, Zsasz arrives under orders from Falcone and engages in a gunfight with Gilzean, where he shoots Butch in the leg after he kills one of Zsasz's henchwomen. Mooney and Butch try to block off the hit man but he follows them down into the basement, where Butch helps Fish escape out a window, but Zsasz catches Butch and discusses what to do to him, whether he should kill him or torture him. With Penguin struggling to manage his new nightclub, Zsasz gives him Butch who is brainwashed by order of Falcone.
Working for Penguin
After Falcone retires from the criminal life, Zsasz begins working for Oswald and helps him threaten Commissioner Gillian Loeb to reinstate Gordon at the G.C.P.D. and resign his position as commissioner.
Zsaz is sent by Penguin to kill Mayoral candidate Randall Hobbs. He enters and says he was there to volunteer. He singlehandedly kills all five of Hobbs' security guards and then chases the candidate out of the building. The Strike Force arrives outside and tries to stop Zsasz. A gunfight ensues and they bring the candidate to safety. Zsasz gets shot and shoots a fire hydrant on his way down, allowing him to escape unseen.
After Butch is freed from his conditioning by Theo Galavan and his sister Tabitha and betrays Oswald, Zsasz, and his crew, are sent to kill Butch who has set up his own gang and hanging out at a bar. The gang retreat and Gordon and Bullock are forced to hold the fort until reinforcements arrive. Zsasz retreats after a barrage from heavy machine gunfire.
Zsasz was present at a meeting along with other members of the Cobblepot crime family when Oswald (now the mayor of Gotham City) stated that he wanted the leader of the new incarnation of the Red Hood Gang dead and his head on a stick for destroying a statue of his late mother. Zsasz later took part in a scheme with Oswald's chief in staff Edward Nygma to expose Butch (now working with Oswald again) as the culprit for instigating the attack. During a party celebration held by Oswald at a nightclub The Sirens, Zsasz and Nygma convince Butch that they want to break off from Cobblepot and try to convince him to execute him wearing the Red Hood mask. But when Butch is skeptical, Zsasz reveals his underlings have his former lover Tabitha Galavan hostage in the kitchens, which pressures Butch to commit the act. Wearing the red hood Butch shoots at Oswald when he is on stage, but it turns out the bullets are blanks. Zsasz sneaks up on Butch and shoots him down, and Nygma unmasks Butch, showing him it was all a setup and convincing Oswald Butch has turned on him. Tabitha manages to break free and attacks several goons and allows Butch to attack Nygma, however Oswald knocks Butch out who is subsequently arrested and taken away.
Zsasz is called in by Mario Calvi who tells Zsasz to hold Gordon at gunpoint. After holding Jim prisoner for a couple minutes, Zsasz tells him that he is free to go, as he was only instructed to keep Jim occupied for a few minutes. Jim asks Zsasz for his weapon back, but Zsasz declines. Jim then knocks Zsasz out, retrieving his weapon and sets off after Mario.
Zsasz later visits Jim Gordon after Mario Calvi's funeral where he has a message. When Gordon least suspects it, Zsasz will avenge Mario on Carmine Falcone's behalf. Before leaving, Zsasz tells Gordon "Nice shot on Mario. I never liked him." While trying to follow Dwight Pollard, Gordon and Bullock are ambushed by Zsasz and his henchwomen. While behind some garbage cans, Gordon tells Bullock that Falcone placed a hit on him. Gordon makes a run for it in order to draw Zsasz' firepower away from Bullock. Taking the fight to the kitchen, Gordon ends up in a shootout with Zsasz which resulted in both of his henchwomen getting shot. Gordon then fights with Zsasz and manages to subdue him. After recovering, Victor Zsasz raids Gordon's apartment at the time when Bullock was visiting. As Gordon, Bullock, and Zsasz have each other at gunpoint, Carmine Falcone shows up stating to Zsasz that the job is cancelled. Zsasz then takes his leave.
Whilst a sociopath and cold-blooded killer, Zsasz demonstrates loyalty to both Falcone and Cobblepot in turn and seems very willing to be directed by a boss, as long as he is let off the leash at regular intervals. He appears to view his killing as a form of art, planning meticulously in many cases, always prepared with an escape route, and happy to confront multiple gunmen head-on. He demonstrates a substantial degree of discipline and professionalism when carrying out his tasks. His formidable combat skills and natural wits make him one of the deadliest and most feared killers in Gotham. He shows neither remorse nor empathy at any point. He also has a morbid sense of humor.
Zsasz's true loyalties seem to lie ultimately with Carmine Falcone, since he came to "guard" Jim Gordon at Falcone's request even when he was supposed to be working for the Penguin's organization. Although he continues to work for Cobblepot, he takes jobs for Falcone whenever he is needed. He maintains his loyalty to Penguin as one of his top enforcers.
- Like in the comics, Zsasz carves a tally mark into himself for each kill. In the comics, which are set several years after the series, his body is nearly covered in the cuts he's made.
- Zsasz's surname is a palindrome.
- The character was created by Alan Grant and Norm Breyfogle. He first appeared in Batman: Shadow of the Bat #1 (June 1992) and is usually depicted as a nihilistic serial killer rather than a professional hitman. Zsasz's name is derived from that of real-life psychiatrist Thomas Szasz, whose name Grant saw while visiting a library.