Bullock began his career as a detective in the GCPD. On the night Thomas and Martha Wayne were killed by Jack Napier, Bullock was the first responding officer on the scene. A photograph of Bullock comforting their orphaned son, Bruce, was printed in the Gotham Globe. In around the 1940s, a waitress named Maria Kyle conceived a child with Bullock, naming her Selina. Growing up, Selina still knew who her father was and loved him very much. Bullock loved her as well which is why he would visit his daughter is Oasisburg whenever he had the chance and even attended her karate tournaments. Bullock had a loving relationship with his daughter, until he discovered Selina was working for his boss Gillian B. Loeb as his secretary. Bullock then wanted nothing to do with Selina anymore due to him knowing that Loeb is corrupt.
Batman Year One
Bullock is one of the members of the GCPD trying to bring down officers on the payroll of crime lord Carl Grisson Although Bullock never directly came face to face with Batman, he discarded all claims about the mysterious vigilante, and even belittled reporter Alexander Knox for his belief in him. Bullock was under a lot of pressure from Detective Max Eckhardt, whom he was trying to prove was corrupt. After leaving Bullock to meet Napier, Eckhardt accepted a bribe him. Napier informed Eckhardt that newly-elected District Attorney, Harvey Dent, was nosing around one of Grissom's front companies, but Eckhardt brooded that if there's a problem, it's best to bear with it. Napier then told Eckhardt of his plan to overthrow Grissom, but Eckhardt merely scoffed at him, and told him that he had no future. A brief struggle ensued, and Eckhardt only decided not to shoot Napier when Napier's thug Bob aimed a gun at his face.
Eckhardt later received a call from Grissom, who informed him that he set up a trap for Napier and his men at Ace Chemicals (Napier had an affair with Grissom's mistress, Alicia Hunt, something Eckhardt himself apparently informed Grissom about, and Grissom wanted revenge), and requested that Eckhardt ambush and kill Napier with a squadron of police officers. A gunfight erupted at Ace Chemicals between the police and Napier's Hoods. Bullock, who was attending Bruce Wayne's party at the time, was informed by Charlie, a sergeant and his right-hand man, that had received an anonymous tip that Jack Napier and his men were at Ace Chemicals, and that Max Eckhardt lead a squad to take them down. They both then left unnoticed. Bullock had plans to capture Napier alive after deducing he was set up by Grissom and wanted Dent to offer Napier a deal to testify against Grissom. Eckhardt attempted to escape, but was shot in the chest and killed by a vengeful Napier, who fell into a vat of chemicals moments afterwards during a fight with Batman, and started his transformation into the Joker. Gordon spotted Batman for the time. Standing above a mobster dangling in fear after being pulled by a line shot from his grappling hook pistol, he saw the silhouette of Batman. He was left in awe, with mouth agape.
Batman later met with Bullock and Harvey Dent during the Joker's reign of terror. Batman gave them information to give to the press on Joker's Smylex, which were chemically altered cosmetic products that caused the wearers to laugh hysterically until death, where they were left with ghastly grins on their faces. Dent agreed to this, however, Bullock, who had a grudge on Batman for dropping Napier into the vat, wanted to have a forensic chemist named Julia process this before turning it over to the press.
Bullock witnessed Joker's last stand from afar at Gotham Cathedral. He attempted to move a massive bell blocking the entrance to the stairwell, by himself. After he ordered searchlights put on the tower. Later he saw the Joker's body land on the ground after Batman was through with him. He then examined a laughing bag he had activated while falling to his death. Bullock attended the public announcement of the Batsignal, with all Gotham City officials in attendance. After Mayor Borg read a short letter left with the gift, Dent dramatically presented it. Bullock was upset by this since he felt Batman created the Joker.
Sometime later, when the Red Triangle gang attacked the Lighting of the Tree ceremony, the Tattooed Strongman threw a sled at his cruiser. Rather than emerge from the vehicle with his fellow officer and draw their guns on the unarmed circus strongman, Charlie promptly radioed for the Batsignal to be turned on. Bullock then allowed Batman to defuse the situation. The Mayor later attempted to thank Batman for his assistance.
After Penguin and Catwoman executed their plan to kidnap the Ice Princess and frame Batman, Bullock appeared on television presenting Batman's bloodstained Batarang found in the missing girl's dressing room. Later when the Ice Princess fell to her death at the re-lighting of the Tree ceremony, Bullock and three of his men rushed to the rooftop Batman was seen at. Bullock and his men immediately started firing on Batman. He tried to pursue Batman in a car chase, however, Batman was able to escape.
Later, Commissioner Loeb's plans to make Penguin the new mayor are ruined, when Bruce Wayne, from the Batcave, jams the microphones during Cobblepot's speech and plays some rantings Cobblepot had made towards the city while controlling the Batmobile with Batman inside it. Cobblepot's true personality and his schemes are uncovered, and he loses his popularity and is forced to return to the sewer, especially after Loeb abandons him. At Bruce Wayne's annual masquerade party, a suspicious Bullock went to confront Loeb demanding to know if he was involved with Cobblepot and the Red Triangle Circus Gang. Loeb refused to deny or confirm it, however, he threatened to end Bullock's career as a lieutenant. After Loeb's death, Bullock was appointed to be the new police commissioner. He was grateful that Loeb's evil finally ended, and he begrudgingly admitted to Charlie that he had doubts Batman killed the Ice Princess.
Bullock is described as a "gruff, determined city police officer" who believes true justice can only come from law and order. He can be arrogant to the point where he seems to think he can go in a person's house without a search warrant or an arrest warrant when he said, "I have a badge and a gun, that says differently". He initially hates the Batman because he believes himself to be responsible for all the madness in Gotham even though he was grateful for some of things he has done. Bullock can be hijacked by emotions very easily.
- High-level intellect/Expert detective: As a previous police detective of the Gotham City Police Department, Quentin has proven himself a highly skilled detective. However, he does jump to conclusions. He was able to deduce Napier was being set up, deduced Loeb was in league with Penguin before betraying him, and had doubts Batman had anything to do with the Ice Princess being abducted.
- Expert marksman/Firearms: As a former police detective, Bullock is shown to be an expert marksman and profident user of guns.
- Police training: Bullock has received training, as all Gotham City Police Department members do.
- He gets stressed easily and his hijacked by his emotions. Although he had doubts Batman kidnapped the Ice Princess, he still went along with what the public believed since he still has a grudge on Batman for what happened to Jack Napier and blames Batman for causing Napier to become the Joker.
- Guns: Bullock is very proficient in using guns.