The Uncle Grandpa pilot was created by former Chowder storyboard artist Peter Browngardt in 2008, but aired online in 2010 on Cartoon Network Video as part of The Cartoonstitute. Just like the Regular Show pilot, the Uncle Grandpa pilot was successful, but it didn't green lit into it's own show yet. In 2011, Secret Mountain Fort Awesome aired on Cartoon Network, and was bad-mouthed by people, because it looked disgusting. Browngardt decided it would be the right idea for Uncle Grandpa to have its own show as well. In 2012, Cartoon Network announced two new shows, "Uncle Grandpa" by Peter Browngardt, as well as Steven Universe by Rebecca Sugar. Uncle Grandpa aired on September 2nd, 2013 on Cartoon Network.
Uncle Grandpa stops by children's houses every day to see how they are doing. The children start off hating him or distrusting him, but after a great big adventure, they end up liking him.
- Uncle Grandpa (voiced by Peter Browngardt): The series main character, Uncle Grandpa has an L-shaped head, a pink nose, a red fanny pack that talks, a propeller hat, and overalls. He appears very stupid and has many floating heads and differently random bodies. He would make anything awesome for the kids. His catchphrase is "Good Morning".
- Belly Bag (voiced by Eric Bauza): Uncle Grandpa's talking red fanny pack who holds all of his priceless valuables. He even has an elevator inside of him that can lead to many secret dimensions.
- Pizza Steve: (voiced by Adam DeVine) A talking pizza with sunglasses who is friends with Uncle Grandpa. He believes he is the best thing in the world.
- Mr. Gus: (voiced by Kevin Michael Richardson) A large green lizard who is Uncle Grandpa's sworn protector and body guard. He is obviously a parody of Godzilla.
- Giant Realistic Flying Tiger: A photoshopped real photograph of a tiger that Uncle Grandpa rides on to get around.
- Beary Nice: (voiced by Audie Harrison) – A teddy bear accompanied by Hot Dog Person, and who sees the world as being very nice, but doesn't notice Hot Dog Person when he is in danger, and he usually ends up with good experiences. His catchphrase is "That's me!".
- Hot Dog Person: (voiced by Eric Bauza) – A hot dog accompanied by Beary Nice, and who sees the world and new things as being very dangerous, he usually ends up having bad experiences. His catchphrase is also "That's me", but in a sad, depressed voice.
- Tiny Miracle: (voiced by Tom Kenny) – Tiny Miracle is a robot that can perform miracles by just a series of unnecessary moves, and then technically performing the miracle only to lead up to another tiny miracle. He sounds like a 1980s microphone. According to Mr. Gus, he is Uncle Grandpa's helper. He can be summoned by saying "It'll take a tiny miracle to..." and then the task the person is attempting. His catchphrase is "Did somebody say "tiny miracle"?"
- Charlie Burgers: (voiced by Brian Posehn) – A talking dog that befriends Uncle Grandpa and his friends. He can be well behaved and he enjoys going on adventures with Uncle Grandpa. His catchphrase is "I love my ball!"
- Frankenstein: (voiced by Mark Hamill) – A tag-along with Uncle Grandpa in his adventures. Frankenstein appears randomly in the series, but rarely, if ever, has anything to do with the plot. Because of the condition, he is unable to talk, though he will occasionally roar. He is usually seated next to Uncle Grandpa in his chair.
- Xarna, She-Warrior of the Apocalypse: (voiced by Eric Bauza) − An overly-muscular, masculine female warrior. She is on a mission to get some gas for her motorcycle. Her catchphrase is "I don't like your mouth."
- Aunt Grandma/Priscilla Jones: (Voiced by Lena Headey) − Uncle Grandpa's nemesis with a British accent who wants revenge on him for ruining her science project and rather than help her played hacky sack instead resulting in her getting second place in the science fair. She prefers to solve children's problems using simple practical solutions, the complete opposite of what Uncle Grandpa does. Her catchphrase is "Beautiful Morning!"
- Evil Wizard: (Voiced by Rob Schrab) − A wizard that goes around trying to make everyone's day horrible by humiliating them but he actually makes their lives better. His catchphrase is "Behold! I am Evil Wizard!"
- Crazy Baby: - is the main antagonist of Driver's Test. He is voiced by Eric Bauza.
- Angry Man Johnson:(voiced by Roger Craig Smith) – Angry Man Johnson is a grumpy man who hates Charlie Burgers. Judging by his name, he is always angry at everyone, including Uncle Grandpa. Angry Man Johnson frist appears in "Charlie Burgers".
- Tiger Trails (December 16th, 2014)
- Good Mornin' (April 7th, 2015)
Cartoon Network (2013-2017)
Boomerang SP (2017-2018)