Penny is the lightest of all the puppies, and has relatively few spots. The spots she does have, including those on her ears, are very small and round. She is also one of the few girls of the litter, and is presumably depicted as "Daddy's little girl."
Penny first appears watching TV with the other puppies, and appears to be the closest to her dad, Pongo. Unlike a few of her siblings, her name has no significant meaning to her appearance, though she is notable for having a fewer amount of spots than the rest of the Dalmatians. Along with her siblings, she is kidnapped by Horace and Jasper for Cruella to make them into a fur coat. With the help of Sgt. Tibbs and her parents, she escapes and returns home.
Penny's role greatly decreased in the sequel. She is often seen alongside Lucky and Freckles, and like the rest of her siblings, is kidnapped by Horace and Jasper for Cruella, and is rescued by Patch later on.
Penny was going to be one of the major pups in the series, alongside Lucky, Cadpig, Rolly, Spot and Patch. Her original characterization was that she was very dictorial and a control freak. Disney thought there were too many main characters in the series, so Patch became an extra, while Penny was written out of the show. A preview for the series (as well as for Recess) which was shown on the 1997 tape of 101 Dalmatians has a clip of one of the artists drawing a female puppy who never appeared in the final product, who is speculated to be Penny.
- In some accounts, it is said that Patch and Penny were never seen apart from one another, so it's led to a suggestion that Penny could be Cadpig in the animated film, due to a similar friendship with Patch in the novel.
- In various dubs of 101 Dalmatians: The Series, Cadpig's name was changed to Penny. Many fans believe that Penny was made as a substitute for Cadpig in the movie.
- Before the puppies roll in the soot, Penny asks, "Mother, should we?", but her collar is incorrectly colored red (which the boy puppies are given in the film).
- Penny doesn't appear in the live-action films; however, one of the tie-in books to 101 Dalmatians, which came with finger puppets of two puppies, included her as one of the finger puppets. She was given a red collar.