Sebastian takes on the appearance of a tall, handsome, youthful male adult with black hair, red eyes, and pale skin that has a grayish tint. He typically dresses in an outfit that consists of black trousers, a six button double-breasted tailcoat, and a grey vest. He has the Phantom hive crest on his shirt cuffs and tie. He also sports a pocket watch with a chain and chained silver lapel pin bearing the Phantom hive crest, traditionally worn by the house's head butler.