Grady Harris is a member of Merton's Gang.
Grady and his cousin Merton ran a crew a few years back. Grady and his fellow gang members interrupt a wedding reception and demand cash and jewelry, but are stopped by Victor Zsasz. He tells them that they must be licensed by Penguin to commit crimes. After the gang refuses to back down, Zsasz shoots Merton's finger off, telling the rest to leave the loot behind which is then taken by those who have licenses. After being told about the licenses, Grady and his fellow gang members arrive at Gotham Asylum to see Jonathan Crane. The warden, Reed explains the toxin his father injected him with overloaded his fear response, and that he uses that to control Jonathan. Merton explains that he needs Jonathan's fear serum, and pays Reed to release him. Grady and the gang take Jonathan back to his childhood home and uncover a chest full of Gerald Crane's notebooks and chemicals. They torment Jonathan by putting a scarecrow on display while he creates more of the serum for them. After receiving the serum from Jonathan, Grady and his fellow gang members successfully rob a bank. After receiving a name from warden Reed who mentioned that he was threatened to release Crane to them, Jim and Bullock track down Grady and his gang, but Grady and Merton get the jump on them. They tell the detectives that they are outlaws with a code and are nothing like Penguin. After seeing Penguin threaten to destroy the gang on the local news, Grady and the gang set a plan in motion to take down the Penguin. They arrive at The Iceberg Lounge and linger in the kitchen where they are quickly caught by Penguin and his men. Penguin puts them on display and makes a speech about how he is the one keeping Gotham safe, not the GCPD. After the lights go out upon Ivy Pepper turning them off, the gang members attempt to escape with the crowd and Grady successfully escapes while Merton and the others are defeated by Gordon, Bullock, Zsasz, Bruce Wayne, Alfred Pennyworth, and Tabitha Galavan. Grady returns to fetch Jonathan Crane to force him to make more fear gas. However, he is shocked to find that Jonathan is now wearing the scarecrow costume, and is sprayed in the face with the fear serum.
After Merton confessed to where Jonathan Crane is, Gordon, Bullock, and the rest of the GCPD find Grady tied up dressed as a scarecrow stating that Scarecrow is coming. At the time when Gordon helps Alfred secure Bruce's release from police custody, Grady was shown to still be affected by the fear gas.