MudBud is the filthiest of all the Buddies, hence his name. He wears a blue handkerchief for a collar and usually ends his sentences with "Dude." He likes rolling in dirt patches and hates getting soapy baths. He also appears to be quite mischievous as B-dawg described him as being a "repeat offender" when it comes to getting a time out. In Snow Buddies, the white snow he was trudging through in washed away all the mud on his fur, much to his dismay. Luckily, when the Buddies got back to Fernfield, MudBud rolled in a patch of dirt to make his fur look the way it used to. He lives in Fernfield, Washington, with his famous all-star father Air Bud (Buddy) and his mother Molly. His owner is Pete, a boy who was at first addicted to handheld video games, until MudBud taught him how to loosen up and be more outgoing.
In Air buddies him and his siblings caused a huge mess in the house while they had a pet sitter, prompting their owners to finally decide to give them to separate new owners. Like the others, Mudbud didn't like that idea. Buddy showed him to a boy called Pete who was addicted to video games and hated going outside but Mudbud didn't want to go with him. The next day Mudbud suggested they ran away, a plan which the others agreed to. However when their parents came looking for them, workers of Selkirk Tander kidnapped them and later began hunting them. The Buddies had to go all the way to Wine country to find them. Twice Mudbud got into a fight with his brother, B-dawg. At the end of the film he was given to Pete and the puppy taught him to be more out going and to hang loose.
In Snow buddies, Mudbud and Pete are shown to have bonded with each other and Mudbud stated that "the dudes finally learning to hang loose". After they were accidentally shipped to Alaska the Buddies met a Alaskan husky called Shasta. To his dismay, the snow had made his fur clean. After entering the dangerous dog sled race to help Shasta and his owner accomplish their dream as well as getting to the airport, he was in the end of the team with Budderball. When they won their parents had found them and couldn't recognise Mudbud because he was so clean. Luckily when they got home he rolled around in some dirt and he happily said "Fernfield home sweet dirt!" and re-united with Pete.
In Space buddies, he was shown getting a time out for making a mess in the house. His siblings freed him so they could all go and watch the launch of the Vison-1 space ship. When they tried out the space suits, Mudbud immediately rolled around in dirt to make it filthy. When they were accidentally shot into space and arrived at a former Soviet space facility, Mudbud suggested they try to barge the door open using Budderball which failed. At the end of the film the puppies were honoured in front of everyone the title of "Space buddies" and were given wings of heroism by Pi. They were also all over the news when Dr. Finkle purposely released the news of puppies in space to the media.
Like his sibling's, Mudbud expressed doubt on the existence of Santa Paws, in Santa buddies, but soon encountered his troubled son Puppy paws. Mudbud tried to teach him how to behave like a normal puppy, but he ended up messing up his house which made Mudbud's owner's force him to wear a clean coat as punishment. Puppy paws overheard the Buddies complaining about him and was saddened to hear this, however, it resulted in his capture by Stan Cruge. The Buddies soon realised that they were being unfair to Puppy paws and, together with Eddie, rescued him from the pound. Eli the head elf then came up with an idea that Puppy paws can use his crystal to make the sled fly back to the North pole, with the Buddies pushing it. Luckily, since they remembered their experience in Snow buddies, the pup's pulled the sled to the North pole and later delivered presents around the world.
During Halloween, Mudbud dressed up as a pirate like Pete but while trick-or-treating, they encountered the evil Halloween hound and Warwick, who B-dawg accidentally released from his mirror after 75 years. Pip, the friendly ghost, tried warning them about their plan and, after briefly being scared of him, the Buddies and Zelda helped Pip get back into his old body. However, the hound captured them and bought them back to the manor where Pip and Hoot sacrificed themselves to help them escape the demonic dog. Now with all five souls, he released the spirits of the Netherworld. Thanks to B-dawg and his plan and the kids defeating Warwick, the world was saved and Mudbud and his sibling's reunited with their owners.
In Treasure buddies (which presumably takes place between Santa and Spooky buddies), Mudbud and his sibling's visit the Fernfield history museum, where Grandpa Thomas tells the story of when he was a young archaeologist looking for the lost collar of Cleocatra with the Buddies grandfather, Digger. Mudbud remarked that Digger was "the coolest dude" and Buddha replied by saying that since they both love dirt Digger's spirit could be with Mudbud. Thomas gave the dirty pup Digger's favourite bandanna, when Philip tells them that he is going to Egypt and convinces Thomas to go with him, who takes Pete as well. However, the evil cat Ubasti plots to steal the collar and make cat's rulers of all species. The Buddies chase them her to Egypt, where they eventually foil her evil plan, as well as assisting Cami in finding her tribe. Philip is arrested by the Egyptian police and the Buddies are praised as heroes; Babi dubs them as "Treasure buddies".
Budderball and Mudbud get on with each other and are often seen working together such as in Snow Buddies when they were both at the back of the sled team since they were "the strongest" and in Treasure Buddies when they were in the same group when they split up to search for Mudbud's owner. Mudbud stuck up for his brother when B-dawg snapped at him in Air Buddies. Like the others, he warns his siblings not to pull his paw, knowing that this causes him to pass unbearable gas.
B-dawg and Mudbud behave similar in that they both try to act cool. However Mudbud prefers not to stress over small problems and "hang loose" while B-dawg likes showing of how cool he can be. Despite the big squabbles they had in Air Buddies, the two are still close brothers. The fights they had were mainly due to their frustration at their long journey to free their parents while being hunted. However they still remained close brothers and quickly made up with each other. In the Snow buddies "buddy bites" they would often make jokes at each other.
Rosebud is protective of Mudbud, as shown in Space Buddies ,when she tried to focus her brother's attention to freeing Mudbud from his time out cage, and in Santa Buddies, when she was startled that Mudbud was in big trouble and had to wear a "clean costume". In Treasure Buddies she tried comforting him when he felt guilty about bringing the rest of his siblings to Egypt when his owner was in trouble.
Mudbud and Buddha have never argued and get along fine. Buddha broke up the fight between his siblings in Air Buddies and Mudbud views his opinions as correct as shown in Snow Buddies and Santa Buddies when he says "the zen dude is correctumundo!"
Mudbud takes after his father in that he loves playing Volleyball.
When the Buddies introduced themselves to him, Shasta wondered why he was called Mudbud as the snow had made him clean. At the end of the movie Mudbud was, as well as his siblings, really sad to say goodbye to their new friend. Mudbud reminded him to "hang loose".
- Mudbud mainly wears a blue handkerchief with his name on throughout most of the films. But in Santa Buddies he wore a red one and in Treasure Buddies he wore Digger's favourite bandanna.
- B-dawg noted that every time it's a rainy day Mudbud repeatedly gets a "time out" because he rolls around in mud a lot.
- Mudbud appears to be the youngest boy of the litter.