Ken sees the girls as older sisters and has to often put up with them, though he still cares for them deeply. Ken interchanges between calling Professor Utonium Papa and Professor. During a serious situation (such as a monster attack or investigative purposes) he will try to refer to Utonium as "Professor," but in less serious situations (like packing a lunch) he will call him "Dad." Ken often corrects himself, because he usually uses the wrong honorific (e.g. "Dad, I mean, Professor").
In Episode 26, it is revealed that Ken's mother works on a space station, therefore making her very busy and unable to be with Ken. Thanks to the girls and Santa Claus (whom he believed did not exist at first based on a 70% possibility), he was able to see her and is now able to communicate with her clearly on the lab's monitor.
In episode 37, when the Powerpuff Girls Z are "grounded" from using their powers for a day when they have to take a test in school, Ken fills in for them, donning a superhero suit consisting of a black bodysuit, a white cape, white gloves, white boots, a red vest with gold shoulder pads and a yellow "Z" on it, and a blue helmet with the yellow letters "KK" on it, while brandishing a blue polearm with a yellow "U" at the end, and calling himself "Ken Kitazawa Z." Despite having no powers or attacks, he uses traps and other props as weapons when he defends their lab from the Gangreen Gang, ultimately driving them off by tricking them into drinking bottles of hot sauce (thinking they were the containers of Chemical Z).
Ken's pre-production art bares a strong resemblance to Dexter from Dexter's Laboratory, even the current incarnation. However, in one of the special edition DVD booklets, it is explained the design originated from Kid Utonium (the original Professor as a kid) from the original series.
- In the original Japanese version, Ken is voiced by Makiko Ohmoto, who is famous for voicing Kirby in the Kirby series.
|Episodes and VHS/DVD releases - The Powerpuff Girls Movie - Powerpuff Girls Z|
| Characters: The Powerpuff Girls (Main: Blossom - Bubbles - Buttercup Other: Bunny - Bullet) - Professor Utonium - Mayor - Ms. Bellum - Ms. Keane|
Mojo Jojo - Fuzzy Lumpkins - HIM - Princess Morbucks - The Rowdyruff Boys (Brick - Boomer - Butch) - The Amoeba Boys - Sedusa - Gangreen Gang - Minor characters
| Video Games: Fifth Generation Games: Chemical X-Traction (PS, N64) - Bad Mojo Jojo (GBC) - Paint the Townsville Green (GBC) - Battle HIM (GBC)|
Sixth Generation Games: Relish Rampage (PS2, GCN) - Mojo Jojo-A-Go-Go (GBA) - HIM and Seek (GBA)
Seventh Generation Games: Demashita! Powerpuff Girls Z (DS)
PC Games: Mojo Jojo Clone Zone - Princess Snorebucks - Mojo Jojo's Pet Project
|Misc. Superpowers - Townsville|
|Creator: Craig McCracken|