In his debut episode Nano, Harry "The Schlub" Parker was a petty con artist and street vendor. After ripping off a man's wallet, Harry ran into the Nanobots which using Harry's broken toys, created a body. Harry is petrified at first but then he sees a demonstration of the nanobots abilities and becomes intrigued with the criminal possibilities. Harry adopted the Nanobot and decided to use it to break into stores. He used him to break into several stores around and in the 2nd Time Around store. One night, he and Nano broke into April's store 2nd Time Around. However, Nano was busy stealing the theater masks. When they were leaving, they were caught red handed by Casey Jones. Nano took apart a car and made a new body. Casey was easily beaten by Nano but the Turtles heard a noise and went to investigate it. They encountered Harry and Nano. Harry thought the Turtles were martians and that they were invading. Nano defeated the turtles but Don managed to cut a piece from Nano during the fight and discovered that Nano's weakness is extreme heat. Harry and Nano went to the junkyard and made it their hideout. Harry told Nano maybe it's time to leave town because he thinks the Turtles are trying to take Nano back where he came from. The Turtles tried to take Nano apart by cutting him fast and getting him into the crusher but Nano kept coming back. The Turtles caught Nano with an electro-magnet but Harry tries to save his son by turning off the electro-magnet. However, Nano fell into the furnace and said, "Daddy" while melting. Harry grabbed one of Nano's masks and was crying and apologizing about how he broke Nano. Harry is arrested afterwards by the local authorities.
In his next appearance The Return of Nano, he is transferred to a new prison. Harry is seen playing a card game with other prisoners and won but when he pulls his gains, a card falls out of Harry's sleeve which reveals he's been cheating the whole time. The other prisoners prepare to beat up Harry but Nano comes in and breaks his "dad" out of prison. Nano then goes back to the lab where he was created, kidnaps Dr. Marion Richards and builds a house in the lab wanting to have a "family". But both began arguing which angered Nano, who wanted to have a happy family. In order to make its “father” happy, Nano grabs the loot that it had stolen with Harry its first time out (which it had stored on a "Family Fun" display in the amusement park so all families could enjoy it). Harry is happy to see his treasure and asks to be let go, as does Dr. Richards. Nano gets into a tantrum and begins smashing up the park. When Nano was defeated by Don and April, Harry was arrested again and sent back to prison despite his claims that he had been kidnapped from prison.