Grampu is Oobi and Uma's grandpa and guardian. He almost always has his hands full taking care of the kids. His biggest goal in life is to make sure his grandchildren grow up smart and happy. Grampu introduces them to new ideas, like how to paint a picture or make music, on a daily basis. He thinks being Oobi's grandfather is "lovely."
Grampu loves to cook, though the kids tend to make messes with the food he serves them. He usually wears an apron and a chef's hat when he's working in the kitchen. Grampu has a crush on Oobi's piano teacher Inka and has taken her on a couple of dates. The kids often unintentionally embarrass him when he tries to impress her, but she never minds.
A running gag throughout the show is that Grampu has terrible luck, despite his good intentions. More often than not, when he tries to get the kids to try new things, it ends in a good time for them and a messy disaster for him. From getting covered in pizza dough to having to clean up a tub covered in mud, Grampu has seen it all. It annoys him a bit, but he never lets the kids know, since it would spoil their fun.
Grampu's catchphrase is "Lovely!" and he applies this phrase to almost every situation. Although he is Oobi and Uma's grandfather, he is not married and only one of his children—Aunt Oota—has ever been mentioned on the show.
When Oobi started out as a series of two-minute shorts, Grampu had the least screen time out of the four characters. Out of the main cast, he made the least appearances in the shorts and was actually absent in more shorts than he was seen. However, when the show was turned into a full-length program, Grampu's role was expanded and he became much more prominent. He was often written as a foil to the kids, or as someone to give them advice and knowledge. While Uma and Kako were absent for many stories, Grampu was only absent for one full-length episode.
In an interview with the Newsweek magazine, Josh Selig mentioned that unlike the other puppeteers of Oobi, Tyler Bunch intentionally left his arm unshaved so that Grampu would have the appearance of an elderly grandfather. By comparison, the other main cast members all had to shave their arms regularly because they played younger characters. However, Tyler still visited a manicurist to get his nails touched up every week during production. (source)
While Oobi was airing, many parents and older viewers sent letters to Noggin asking why Grampu was Oobi's only guardian. The answer? Oobi's mom and dad are "still around," but they're intentionally never shown. The creators wanted to represent a nontraditional family, so they decided to have Oobi live with his single grandpa. Many kids are raised by their grandparents if their mom and dad are away for work or military service. Giving representation to non-nuclear families was important to Noggin, whereas revealing Oobi's parents just wasn't important to the stories that the crew wanted to tell.
Grampu is a fair-skinned hand puppet with grayish-brown arm hair. His fingers are curled in the front and his thumb acts as his lip, giving him a "toothy" look compared to the kids. He is the tallest of the main characters.
He has hazel eyes that are a little bigger than Oobi's. While Oobi's eyeballs are bright white, the whites of Grampu's eyes are actually a yellowish off-white color, adding to his elderly look. He is the only character whose eyes were never updated or changed throughout the show.
When Grampu works in the kitchen, he wears a white chef's hat and a blue/white apron with a bowl symbol on the front. When it rains, he puts on a dark green raincoat with a hand-sized hood in the back. When he goes fishing, he wears a beige bucket hat with a red pin shaped like a fishing lure.