Batman's Database Profile on Harvey Bullock
Bullock is typical of most of the GCPD officers - he's on the take, and uses his position of authority to his advantage. However, careful examination of his record and recent activities suggests he does follow the law when dealing with civilians. Perhaps there's hope yet for Harvey. With the right motivation and direction, he could turn out to be a good cop, but for now he should be considered just as dirty as any other GCPD officer.
Harvey Bullock, similar to other GCPD Officers under Commissioner Loeb, was on the take for various criminal organizations, although to a far lesser extent than most of his contemporaries. At one point, Loeb, under the influence of Black Mask, had Bullock placed as the partner of then-Captain James Gordon to see if he could uncover any blackmail material (as well as given the implied suggestion of arranging a honeypot trap for Gordon). Bullock was skeptical about it working, due to knowing that Gordon did not trust him.
When Batman was discovered at Blackgate Prison in the aftermath of a Prison Riot that was orchestrated by Black Mask (which resulted in the execution of Commissioner Loeb instead of Calendar Man) on Christmas Eve, Bullock, alongside Gordon, tried to apprehend him, but Batman managed to escape via the Batwing. After Batman's departure, Bullock then sarcastically commented: "No such thing as a Bat Man, huh?", which alluded to Gordon's public denials about the rumors about Batman's involvement in ensuring the GCPD arrested criminals.
Later, after Batman had managed to subdue the Joker at the Royal Hotel and left him to be arrested by the GCPD, Bullock, when he arrested the madman, demanded to know where Batman was headed under the belief that the Joker was his partner in crime, and pointed out that it was the only reason that he could think of that the masked vigilante would "jump off a building to save [The Joker's] sorry ass" (which referred to Batman jumping after the Joker after the latter was thrown off the roof of the Royal Hotel by an explosion from Bane's Bazooka).
Bullock later ended up aiding Gordon and the GCPD in arresting Firefly (who was defeated by Batman at Pioneer's Bridge), with Bullock commenting his distrust for Batman, cited that he had a gut feeling the bridge would have been blown up had the Bomb Squad not located the remaining bomb cache at the Bridge and Gordon not given the breach order, and cut Firefly down on Gordon's orders.
Bullock later participated in trying to contain the Joker's escape, as well as quell the Second Prison Riot at Blackgate that Joker had caused. Bullock later radioed Gordon shortly after the Joker's escape attempt had been foiled, learned that Gordon had managed to apprehend the Joker, and that he had help.
Although Bullock did not appear in the game, he appeared in the tie-in comics, Arkham Unhinged and Arkham City: End Game.
After the death of the Joker, Bullock led a group of officers into the evacuated Arkham City where Harley Quinn and her gang ambushed them, but Bullock quickly knocked her out and took her into custody. Bullock later notified Gordon when Harley escaped custody, stole explosives, and captured several SWAT members.
When Arkham Island was bombed due to the Joker's planning before his death, Bullock gave the order to have medical units over at Arkham Island and ordered Vicki Vale and her news team outside Arkham City to fly him over to the island.
When Bullock and his forces arrived at the ruins of Arkham Island, all they found was Batman's Batsuit, which forced them to believe that the Dark Knight had finally perished, much to Bullock's shock. As Gordon found out, he ordered Bullock to make sure that the news did not get leaked to Gotham City, even if that meant keeping the news staff locked up for the night.