Marshall has blue eyes and a white coat with black spots. His standard PAW Patrol uniform consists of a red fire helmet, a red jacket with a yellow collar, and a "pup pack" with a retractable water cannon.
Marshall is the PAW Patrol's fire rescue dog, and as of season two, its medic. He is prone to clumsily tripping over objects on his way to the team's base. His vehicle is a red firetruck that is able to transform into an ambulance.
- Marshall is revealed to have a large fear of flying in the season one episode "Pups Save a Toof". This trait is retconned in season three, in which he is given flight gear without concern and happily flies in Skye's helicopter.