Cat is the greedy but smart protagonist of the series who enjoys relaxing, unlike his brother and closest friend Dog. He often devises plans to trick Dog into getting what he wants, such as making Dog smarter in an attempt to have more in common with him, or having him win a dog sledding contest by training him in a very hard and militaristic manner, and usually, as a result of his greediness and selfishness, these schemes all blow up in his face. The character is the "underdog" of the two. Life has been hard for the both of them, as they have been shunned by society due to their awkward appearance, but Cat always seems to get the short end of the stick in the situations, especially faced with the Greaser Dogs. With his brains and constant ridiculing from the rest of the characters, he is the more defensive and short tempered of the two. Despite his quirks and spats with Dog, he loves his brother with his whole heart. He cares so deeply that he ends up helping Dog in the end once his guilty conscience gets to him.
Cat often wishes he was a normal cat. He's self conscious, clean to a fault and embarrassed at having a slobbering dog for a rear end, and is also the rear end for it. He does love Dog, but he's always using his higher intelligence to rope Dog into his schemes - which always backfire. Though he is attached to Dog, he is considered the main protagonist of the series since the episodes focus on him rather than Dog. He rarely ever gets to relax because of Dog's behavior. That said, he's a generally quiet and homely animal.
Cat is early-to-mid 20s (and 5 minutes older than Dog), his blood type is A+, and his nicknames are Catsie and Catbutt. He likes classical polka, peace and quiet, beautiful women (though most of them hate him), his brother Dog, working with his mind -- but never physical labor. He dislikes pain, extremely loud noise, raucous partying, Winslow, the Greasers, water, amusement park rides/christmas town, being humiliated. His favorite food are white fish chub and cranberries.
Cat is mostly yellow-orange. He has a red oval nose, two eyes with black pupils, and three long whiskers on each of his cheeks. He has two short ears and one dark red spot on his body. His lower half is Dog, who is yellow-orange as well with a purple nose.
Cat has appeared in every episode of CatDog. His first appearance was in "Rugrats" and his last was in "The Wild Thornberrys".