Speed King has a humanoid appearance. It possesses a mannequin-like body and a human-like face with holes for eyes (later depicted as goggles) and a flat raised surface resembling a nose, as well as a fisherman's cap with several metal spikes along the brim and various strings of equal length sticking out from both sides. It has two large horns on each side of its head, a wide mouth, bearing gritted teeth along with pores and bumps over its 'skin'.
It appears to have robotic joints across its arms, and a flat chest covered in pores and bumps similar to its face (earlier depicted with a fur-like texture covering the chest). Speed King's body becomes very skeletal and robotic below chest-level, lacking much of an abdomen and instead having metal bars and other apparatuses connecting it to its lower body.
Speed King's body is wrapped in a bandage-like material, the placement of which varies. Its arms and neck are usually wrapped in it, and in its final appearance, its face is wrapped in it too, giving it a mummy-like appearance.
