Before the School Daze series, the boys as children tricked a younger Trent Boyett into starting a fire which they believed they could put out with their urine but were unable to, resulting in Trent Boyett getting sent to juvie for 5 years. Years Later, he got out and tried to get revenge, but the boys got him arrested again for causing a similar incident.. Later on, Cartman and his friends teamed up with Spongebob, Patrick, and Finn to compete against Scott Tenorman in a swim race in order to get Patrick out of middle school. They succeeded, however, Scott proceeded to take Patrick hostage and threatened to kill him. That’s when Jesus showed up and took him to hell. After that, He made a few minor appearances in the series.
Prior to the High School Years series, Kenny was only seen in flashbacks, cameos, or drawings, and never made any physical appearances, though he was mentioned on various occasions.
Kenny made his first physical appearance in the High School Years series, where Willy comes to his house to reconnect with this brother. The two enter his bedroom and talk for a while, and Kenny tell shim that everything will be alright, and plan to meet again later. He then walks Willy outside and they part ways.
In the Paradise series, Kenny and his friends join Tom and the gang at Nona's house, where they hang out together and help Nona fix her TV cable in the episode "Cable Crew".
In the Animas Extravaganza series, where Kenny, along with his friends, finds Luffy, Usopp, and Chopper outside of his house and lets them stay with him until they reunited with the rest of the crew. Later, Willy finds the trio and takes them back to Milford to meet up with the rest of the gang, but not before a battle with Cartman. He doesn't appear in any AE episodes after that. Near the end of the series, they help out Caillou's team by sending Mysterion to send messages to Tom and co, only for Mysterion to be taken down by Tord Larsson and his alliance.
In the Oak House series, during the Hershey Park Arc, he joins the gang as they go on a trip to Pennsylvania. There, they meet up with the Heroes, and together, they go to Gettysburg and Hershey Park before parting ways.
In the Advanced Education series, Kenny and his friends meet up with Willy after they got arrested for being framed for a school shooting. The boys sneak into the school with Willy, and later joins the gang on yet another trip to the movies, where they see "The Grinch", and go out to eat at Not Your Average Joe's afterwards. Later, they join our heroes again, and together, they go to Plimoth Plantation. He has made a few cameos after that.
In the Senior Year series, He calls his brother Willy on Skype in "Taking Charge". An alternate version of Kenny appears in "Time Rupture 3: Road to Wampanoag", and he is extremely wealthy, unlike his main counterpart. Annabelle has donated money to his family, only for his father to spend it on Lottery tickets, and surprisingly, he actually won, and as a result, the family became very rich. Kenny now dresses formally and acts very rude and snobbish towards those who are of lower class than him, but still gets along with Cartman, Stan, and Kyle. When Alex and Rigby visit their mansion, he is very rude to them.