Casey is pretty thin for a teenager in addition to being taller than April as well as the Turtles (though shorter than most other mutants, including Master Splinter). He has black, medium-length hair and the two front teeth and left lateral incisor of his upper jaw are missing, which he explains were accidentally knocked out by what was then his best friend. His outfit consists of a black bandanna tied around his head, a messy, maroon elbow-length shirt with a short-sleeve gray shirt and a sleeveless black hoodie over it, grayish-blue jeans, black finger gloves that stop at the forearms, and black sneakers.