Mutt & Stuff is an American children's television series airing on Nick Jr. The series premiered on March 6, 2015, with an hour-long pilot and began airing regularly on July 10, 2015. It was created by Sid and Marty Krofft (in their first new product in over a decade) and Bradley Zweig. It stars Calvin Millan, the son of the series producer Cesar Millan. On February 5, 2017, the show was put on hiatus, with no word on season 3.
Calvin Millan and his giant talking dog, Stuff, are in charge of a school for dogs. They are best friends.
- Calvin (portrayed by Calvin Millan) - The dog school's teenage teacher.
- Stuff (performed by Meegan Godfrey, face-performed and voiced by Drew Massey) - Calvin's giant stuffed dog and best friend. In the double-length special "H.R. Pufnstuf Comes to Mutt & Stuff," it is revealed that his uncle is the title character of the Kroffts' earlier series H.R. Pufnstuf. He is very similar in appearance to Pufnstuf as well.
- Zoe and Davenport (performed by Donna Kimball and Drew Massey) - Two cats who comment on the action from a tree outside the dog school where they often exchanging jokes, similar to the characters of Statler and Waldorf from The Muppet Show. They have a tendency to fall out of their tree while laughing at their own jokes while stating that they are OK. They also wear glasses.
- Zippy (performed by Jumpy) - Calvin's pet dog.
- Cesar (portrayed by Cesar Millan) - Calvin's father.
- Melvin (performed by Victor Yerrid) - A red, talking fire hydrant that's outside the dog school. Tells Jokes.
- Grandma (performed by Kuma) - The dog in charge of the puppies while Calvin and Stuff are with the adult dogs.
- Bow Wow (voiced by Victor Yerrid) - The automated A.I. of the Bow Wow Chow Snack Machine that appears in later episodes.
- Marty and Sid (performed by Drew Massey and Victor Yerrid) - Two creepy talking trees that were a gift from Stuff's uncle H.R. Pufnstuf that live on the playground. They are named after the show's creators, Sid & Marty Krofft
- Noodles (performed by Donna Kimball) - A mouse who lives in the wall next to the puppy tunnel; he loves to play jokes by pulling a rope and having confetti fall all over.
- Junior Shades - A small dog who wears sunglasses. He appears in the episode "Dogs on a Plane" as co-captain with Zippy. He appears again in "Sherdog Bones" as a student at Mutt and Stuff.
- Marco (portrayed by Ashton Arbab) - Calvin's cousin and Ceaser's nephew.
- H.R. Pufnstuf (face performed by Donna Kimball, performed by Mary Karcz, voiced by Randy Credico) - Stuff's uncle who's from Living Island in the Krofft Series H.R. Pufnstuf
- Freddy the Flute (performed by Donna Kimball) - H.R. Pufnstuf's magic talking flute.
- Cling and Clang (performed by Arturo Gil and Joseph S. Griffo) - H.R. Pufnstuf's Rescue Racer Crew. Like the original series, they never speak.
- Olive - A skunk that appears in the episode "Bring In Da Noise, "Bring In Da Skunk. All the dogs are scared of and they won't get along. After Noodles disguised Olive, The dogs got along with (Olive) also known as Shirley. While Calvin and the dogs were dancing Olive's dress fell off. All the dogs were scared. Calvin got confused, The dogs did a nose-to-nose with Calvin. Then the dogs were not scared of Olive anymore. And they found out that they could keep her.
- Wally Whiskers - A comedian that appears in the episode, "Sit Stay, Stand Up".
- Meow Meow Kitty (portrayed by Jon Heder) - A villainous cat who takes over Mutt and Stuff, played Jon Heder in season 2.
- Clover (portrayed by Mila Brener) - Cuddles' owner.
- Owen - Sunny's owner.
- Luke (portrayed by Oskar Jacobs) - Dude's owner.
- Dr. Christina (portrayed by Kristina Krofft) - The dogs' veterinarian.
- Popcorn Vendor (portrayed by Omar von Muller) that appears at the end of the episodes.
- Annie the animal rescuer who guest stars and later becomes a recurring character in season two (portrayed by Rachel Eggleston) An animal rescuer who befriends Stuff and the dogs.