Gillian B. Loeb was the Commissioner of the Gotham City Police Department for some years in Gotham City. Loeb made many enemies during his time as commissioner, but was dedicated to stopping crime, and was believed to be un-corrupted (unlike his comics counterpart). However, according to Mayor Anthony Garcia's funeral speech, Loeb had instituted policies that were deemed unfavorable by the public, which may or may not have implied corruption.
After Batman apprehended Carmine Falcone, Loeb viewed him as a threat due to his opposition against vigilance, and ordered a massive task force to arrest him despite Batman's role in the arrest of Gotham's biggest crime lord.
Months later when Ra's al Ghul attacked Gotham, Loeb surveyed the main bridge that attached Gotham to The Narrows. Loeb had allowed all SWAT, Task Force, and most of the GCPD into the Narrows before Ra's let his Fear Gas release from Gotham's railway.
Loeb presumably allowed the Batsignal to be placed atop GCPD Headquarters. In The Dark Knight however, Commissioner Loeb's fingerprint (from a whiskey glass that was inside his desk) was given to The Joker by a corrupt GCPD officer. Loeb's fingerprint was placed on a Joker Card, along with Harvey Dent and Judge Janet Surillo and was given to Lt. James Gordon as who the Joker would target next. Gordon rushed to City Hall and burst into Loeb's office, in an attempt to get him to safety. Loeb did not believe the threat, took out a whiskey bottle and glass, and poured himself a scotch (which implied that drinking on the job was his solution to people making death threats to him, which there were a lot). However, the bottle was poisoned; Gordon realized that only seconds after Loeb started to drink the scotch after Loeb asked how Joker may have gotten his prints as Gordon ran down the list of possibilities, including the alcohol glasses.
Loeb collapsed and died, with smoke pouring out the glass (which implied that the fatal ingredient was a strong acid). Judge Surillo was also killed minutes after Loeb's death. While Loeb's funeral took place, the Joker attempted to assassinate Mayor Garcia, but he was saved by Gordon; Gordon was thought to be dead, but faked his death in order to capture the Joker and protect his family's safety. Gordon then replaced Loeb as Commissioner.
- In the Novelization of The Dark Knight, Loeb's full name was given as Perry Loeb.