Doggo appears to be a bipedal dog monster. He wears a cotton-candy-pink muscle shirt with a picture of a dog on the front, a ninja-like mask, and leopard-print stretch pants. He also has a brown belt, and white tail. His lower paws appear to be bare. He dual wields short swords similar to the typical King playing card.

Doggo's most notable feature is his inability to see stationary objects; he can only sense things that are moving, and he dislikes things and people that appear or transport themselves without physically moving (such as Sans). He seems to be occasionally unsure of himself and, if he sees something, checks to see if it moves again.

His in-battle description notes that his hobbies include "squirrels," which refers to a common dog's habit of chasing squirrels. He enjoys being pet by the protagonist, which can compromise his job as a sentry. It is hinted that Doggo smokes dog-treats similar to the conventional cigarette.