The GZPD made its first appearance in the episode "Prisoners of Love" when Danny goes into the Ghost Zone in order to get back his mother's anniversary gift. Danny is send to prison by then for breaking Walker's rules.
They are seen in "Public Enemies" when they are searching for fugitive prisoners. Then they use Wulf in order to find Danny in Amity Park. They overshadow the whole city to try to capture him, and at the end they turn the city against him.
A few of them make cameo appearances in "Boxed Up Fury." Some of them post wanted signs for Wulf, Vortex, and Undergrowth, making the Box Ghost envious of their high bounties. Another one is later seen asking Argus which way the Box Ghost fled after stealing Pandora's Box.
They appear later in "Claw of the Wild," to search for Wulf. They use other monsters to find him and kidnap Danny's schoolmates at summer camp.
They are last seen in "Phantom Planet," when they help Danny save the Earth.
- Even though they are Walker's minions, sometimes they appear in episodes where Walker is absent. They are also seen much more frequently than Bullet, who is Walker's second in command.
- The GZPD agents have personalities and speak, unlike the two other large groups of ghost minions that were seen.