Kenny made his first appearance in Love 'Em or Leash 'Em. He was created by Phineas Mogg and designed to be a teenager. However, Mogg programmed canine-like traits into to Kenny (hence his model name YK-9), which resulted in Kenny having superior scent, odd habits of of howling, barking, and chasing cats, and a fascination with fire hydrants. Mogg assumed adding doglike qualities to his robotic son in addition to his teenage boy personality would make him more loyal and superior to Dr. Wakeman’s XJ-9.
Kenny and Jenny began dating after she met him by a fire hydrant, which he was staring at intently. Jenny and Kenny's relationship made Sheldon jealous, causing him to do everything in his power to expose Kenny's secret, often failing. As the episode progresses, Jenny soon finds out that Kenny is part-dog, which results in a nightmare of her future with Kenny (living in a giant doghouse, robot puppies, Kenny being caught by the dog catcher), leading to Jenny questioning whether or not she should break up with him. However, due to Kenny's popularity among her school peers, Jenny decides to give Kenny another chance... until Sheldon soon learns Kenny's secret and exploits it at the end of the episode, and Kenny is scolded and dragged home by his father, Dr. Mogg.
Kenny appeared again, with a minor non-speaking role in Agent 00' Sheldon, when an evil organization bent on eradicating all of the robots in Tremorton captured and imprisoned him. Sheldon freed Kenny and the other captive robots at the end of the episode.
AppearanceKenny bears a large physique, similar to that of a football player or professional martial artist. His metal skin is white, like Jenny's, and his "hair/ears" and "clothes" are indigo. When in his normal teenager mode, his mechanical ears are folded down flat to resemble hair, but in dog mode they lift up from his head and appear triangular, like dog ears. In his “dog mode”, Kenny crawls around on all fours and bears a resemblance to a bulldog, being large and bulky with a big lower jaw.
Dr. Wakeman accused Dr. Mogg of stealing the design plans of XJ-9 to construct Kenny, but Mogg claimed he simply "improved" them, believing he had made his creation superior.
When Jenny and Kenny first met and began to date, Kenny proved to be a very sweet and loyal boyfriend to Jenny, and was seemingly the perfect teenage robot boy. When Jenny invited him to meet her at Mezmer's on their first date, Kenny used his powers to make the pizza when the party they attended was nearly ruined by a broken oven. Due to his kindness and abilities, he became very popular among the teens at Tremorton High. However, as Jenny got to know him more, Kenny began to display numerous strange canine behaviors, such as having a peculiar interest in fire hydrants, digging holes to escape his house, chewing on a wrench as if it were a bone, frequently sniffing things due to his enhanced sense of smell, howling at the moon, and showing affection with his tongue (e.g. when Jenny expected him to kiss her goodnight after their date, he licked her face instead, much like an affectionate dog). When Kenny involuntarily entered his dog-mode on his and Jenny's second date, he embarrassed Jenny in front of everyone at Mezmer's, especially when he was unable to resist growling, barking, and chasing Sheldon (when he dressed up in a full-body cat costume to expose Kenny's canine secret), resulting in Kenny wrecking the diner and the party. Jenny broke up with Kenny shortly afterward due to his partial doglike programming.
Dr. Mogg is Kenny's creator, and the two have an odd dynamic that is both parent-child and master-pet, due to Kenny being programmed to act as both a teenage boy and a dog. When Kenny is in his teenage boy mode, he treats Mogg like his father. When he enters dog-mode, Mogg treats him like a pet and often scolds him for misbehavior, such as digging holes in the yard to escape. In Agent 00' Sheldon, it is shown that Kenny sleeps in a dog bed and wears a collar and leash.
- Y and K are both of the letters right after X and J, respectively.
- His "name" Kenny is copied from Jenny's name but the J was changed into a K which ironically is after the letter J in the alphabet.