He is Lt. Pug's childhood bully. He once strapped Pug to an RC car that he crashed (over and over again), and wrapped him up to a fish and toss him in an alleyway filled with cats after he offered to take Pug "out for a bite." It was like that every day for Pug, right before his family moved away. Pug got back at Persian Pete by dumping a can of roofing tar on him. Sadly, years later, Persian Pete found out that Pug lives on the Dearly Farm and sent out a message for revenge.
He doesn't appear until around the end of "Howl Noon". The rest of the episode was about Pug in hiding, and the Bark Brigade cadets were trying to help him get over his fears to get ready for him. Cadpig managed to handcuff herself to Pug and hypnotize him into his past lives to be brave. And even though the pups and Pug were small, compared to other animals, Persian Pete was able to rip off the stump cover to Pug's bunker.
Persian Pete's last act of cruelty to Pug was ripping off the ear of Private Bunny. This made Pug mad enough to face Persian Pete, but before the giant cat could lay a claw on Pug, he used Cadpig as a pendulum to hypnotize Persian Pete into a coward, who ran off after Pug gave out a mild "woof."
He later appears in "Animal House Party", where he has been hired by Swamp Rat to act as a security bouncer, when the swamp creatures take over the Dearlys' house. The pups try to get Pug to evict them, but it seems Pug still has some fear of Persian Pete.
The pups then realize that Persian Pete has "Petting Deficit Syndrome," with such symptoms as sinusitis, a puffy tail and aggressive behavior. When they begin stroking them, he does a heel turn and allies himself with the pups and Pug, driving Swamp Rat from the house.
In the same episode, Pug mentioned that Persian Pete's real name was "Mittens," but it is unknown if this was real or he was just egging him on.