Carlos has black hair, with some of the strands standing up, and also has thick, black eyebrows. He wears black glasses that have a square frame, a cream long sleeved shirt, a light green sweater, a red necktie, brown pants, a black belt with a yellow buckle, and dark brown shoes.
Carlos is the son of Hector and Rosa Casagrande, and the brother of Maria Santiago. He studied a lot, and became a college professor. He married Frida Puga, and has four children with her, Carlota, Carlos Jr., Carl, and Carlitos. He is also Bobby and Ronnie Anne's uncle.
Carlos is a bibliophilic and absent-minded professor. He loves reading books so much, that he does this with other things at the same time. Reading books distracts him from what's happening around him, like he didn't react to Lalo eating the food he's carrying, or on Carl getting injured by a watermelon.