Professor Jonathan Utonium is the father and creator of the Powerpuff Girls and he is Nicole's friend.
Professor Utonium was created from The Powerpuff Girls. Professor Utonium in an attempt "to create the perfect little girls" using a mixture of "sugar... spice... and everything nice" (shown in respective fields of baby blue, light green, and pink). However, he accidentally spilled a mysterious substance called "Chemical X" into the mixture, creating, instead of the "perfect little girls", three girls (each possessing one of the above elements dominating her personality), and granting all three superpowers including flight, super strength, super speed, near invulnerability, x-ray vision, super senses, heat vision, and energy projection.
Professor Utonium first brought the girls to their new school in Megaville. After that he wasn't seen until after the battle between Dexter and Mandark when they went home to rest and Professor was careful to microwave that Gumball and Darwin created Kenneth was created by mixing together various disgusting things (like snotty tissues, bird feces, and regurgitated milk) in a jar and microwaving the jar, inside The Microwave is Chemical X.
Later he appeared when Buttercup came home with a letter from Jack that he had to speak with him because Buttercup was gone wild at the School Dojo with Kendo class. The professor and Jack decided that Courage had to stay with Buttercup to take notes of what she was doing. Later when he came home he said to Buttercup that she must do something besides materials arts. He first suggested science, but that didn't work out so they went with cooking which worked out great.