Dudley Donald Puppy is the titular protagonist of T.U.F.F. Puppy. Although he is still just a puppy, Dudley has the
heart of a pack of full-grown dogs. He supposedly has no fear and hates wearing pants, despite that he wears them in some episodes. Reared on his mother's strict morals, he was brought up strong, goodhearted, and destined to stop all badness and meanness in its tracks! Now if only he could figure it out how to follow that last rule.
The first clues to Dudley's past were shown in "Big Dog on Campus." During his high school years, he looked radically different. Being very skinny with no build, wearing very large braces and glasses, and covered in pimples. It was also revealed that he was a bullied outcast. Dudley's father is also absent and completely unmentioned, leaving fans to wonder where he is although it most likely will never be explained.
One day, Dudley (trying to catch his new super-bouncy chew toy) accidentally foiled a huge crime being committed by the city's resident bad guy crew D.O.O.M. owned by the despicable Verminious Snaptrap. This led The Chief to investigate the scene and eventually bring him to genius inventor / scientist Keswick. It was then the scientist analyzed Dudley's DNA and the T.U.F.F. agents discovered that he is the ultimate mutt: A mix of every breed of dog known to man (with a dash of billy goat that even Keswick can't explain). This was awesome news for Dudley (who became known as "Agent Puppy"), but bad news for T.U.F.F.'s top agent Kitty Katswell, who found him irritating to work with. She was assigned to train Dudley and be his partner, which proved to be more challenging than rewarding. Kitty and Dudley were constantly bickering like a brother and sister, but Kitty found out that sometimes you can teach a young, jumpy dog new tricks. Bad guys need to beware, but so do the good guys, because with Dudley around, you never know just whose wicker furniture he'll chew on or whose garden he'll mess up. Looks like Dudley's heroism is going to need a lot of work.
Although intelligent, friendly, and clever, Dudley is an incredibly air-headed and jumpy dog. As a T.U.F.F. agent, and a dog who loves the feeling of being good, he loves to catch bad guys like Bird Brain and The Chameleon. With his superior DNA, Dudley has tons of canine abilities that make him the ultimate mix of dog breeds and an awesome crime-fighting force. He has the best skills from every doggie gene pool (as well as being part billy goat somehow). With the stupendous speed of a greyhound, the superior sense of smell of a bloodhound, the astounding strength of an Alaskan malamute, and the powerful punch of a boxer, he cannot be stopped; however, Dudley is still a sloppy, excitable pup. Dudley clearly isn't a thoroughly trained dog, and still retains many regular dog-traits like chewing his butt and chasing tennis balls. In addition, he is prone to believing that he is dependent on others (usually, his mother or Kitty). Although he seems to like juice boxes, Dudley also seems to like grapes and anything grape flavored. If he isn't drinking a juice box, he is often seen drinking grape soda and also loves grape flavored snow cones, as seen in the episode Lie Like a Dog. In Mutts and Bolts, Dudley gained "super intelligence" from a lightning strike. This may mean that he will be smarter in the future, but it is most likely that this was only used for a gag.
- According to the creators, he is based off Snoopy.