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 head was then redesigned to have a more rounded shape to it, making him look 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 was decided that one ear would be black and one ear would 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). This was directly mentioned in "A Summer to Remember".
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.
He can be a worrier and is sometimes shown to overreact from his anxiety, becoming overly protective to those around him, which the other Dalmatians have dubbed as "Classic Dylan".
Dylan is a huge fan of anything space-related. He dreams about being the first dog on Mars, owns a "space helmet", moon rocks and a space telescope, imagines himself as a sort of space marine while doing the household chores, and gets excited when he mistakes a garden gnome for a Martian.
Dylan also loves paleontology, collecting fossils and having a plush Diplodocus which he calls "Dippy". Dylan is a giant fan of Poodlewolf, a multimedia franchise starring the daring canine hero of the same name. Dylan loves the Poodlewolf VR video game and the RPG board game, which is similar to tabletop games such as Dungeons & Dragons. Once Dylan got so into Poodlewolf, he thought he was the character.
Dylan has a talent for writing poems. This comes naturally to him. In "Poetry Scam", he was looking at the clouds with Dolly and telling her the words to his poem. It's unknown, though, if the poem is a recent one or not. Dylan wishes the others knew his poems, but he is nervous of crowds, so with the help of Dolly, Dylan's poem was finally 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 most of his biological siblings, Dylan does not speak with an English accent. His only biological siblings to not speak with English accents are the Triple-D.
- 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.
- He has a tendency to breathe like Darth Vader every time he wears a space helmet.