In an early pilot for 101 Dalmatian Street, Dylan's ears were both black, his head was a more block-like shape, and he looked like an adult. His design then developed to have a more rounded shape to it, looking younger, as well as having one black ear with white spots and one white ear with black spots.
Some other pieces of early concept show that Dylan's ears were both going to be white with spots, before it being decided that one ear shall be black and one ear shall be white.
According to the showmakers, the spot pattern on his right ear is similar to that of the constellation Canis Major (the Dog Star).
Dylan comes from Delilah's side of the family and is the more responsible one between Dolly and him. He is a major stickler for the rules, which in turn can make him come across as pedantic and a bit of a neat freak. While sometimes anxious, Dylan is very protective of his family, willing to charge into situations he finds scary if any of them are in danger.
Dylan is a huge fan of anything space-related. He dreams about being the first dog on Mars, owns both a "space helmet", moon rocks and a space telescope, imagines himself as a type of space marine when doing the house chores, and gets excited when he mistakes a garden gnome for a martian.
Dylan also loves Paleontology, collecting fossils and having a plush Diplodocus who he calls "Dippy". Dylan is also a fan of the board game PoodleWolf, a canine version of human RPG board games such as Dungeons & Dragons.
Dylan has an ability to write poems. This comes naturally to him. In "Poetry Scam", he was looking at the clouds with Dolly and telling her words of his poem. It's unknown, although, was the poem a recent one or not. Dylan has a wish of the others knowing his poems, but he is nervous of crowds, so only with the help of Dolly, Dylan's poem was revealed.
Dylan is one for cleanliness, with his wash time being precise, such as teeth brushing and sanitary scrubbing. In "Winter Funderland" he mentions that he has a molting journal.
His mother once said that she wants Dolly to be more like Dylan when she got disappointed in her stepdaughter.
- Unlike his mother and the rest of his biological siblings, Dylan does not speak with an English accent.
- According to "The Daily Puppy", a newspaper given out to promote 101 Dalmatian Street, Dylan is twelve years old in dog years.
- In "Walkies on the Wild Side", Dylan learned he has an allergy to cats.