Harlequin has curly black hair that reaches his cheeks. Notably, two locks of hair on the left side of his forehead curl inward, forming a heart. His face is usually obscured by a white mask with upturned eyeholes. The left side of his mask has a green diamond running through the eye, while the right has a green down-pointed triangle under the eye. His mask almost always depicts a sinister, sharp-toothed grin. Oddly, this is expression is not fixed, his smile may widen, narrow, shift into a smirk or grimace, or disappear entirely. Additionally, the mask's smile is a hole, showing the wearer's teeth. His eyes are a venomous green. They are typically slits or thin rings. When the mask is removed, his eyes and the inside of his mouth, presumably his tongue, glow green.

Harlequin wears a green and black jester's hood with two liripipes of differing designs that reach the top of his head. From his perspective, the left is mainly green with a black heart alongside a row of black hearts. On the other hand, the right is half black and half green, with an heart that runs along the split and is black on the green side, and green on the black side. Both ends are tipped with a bell.

Harlequin wears a black cape with a golden lining, accents, and underside. It is fastened around his neck by a golden strip of fabric. The left side of the cape bears a reversed heart, while the right bears a normal heart. Underneath, he wears a green tunic with two vertical black stripes running along the left side of his torso along with a black belt loosely wrapped around his waist. Additionally, his tunic has a golden panel along the centre, bordered by black stripes, and a golden lining. He has two slightly loose sleeves with differing designs. His left sleeve is entirely black, save for a green stripe running along its length, while his right sleeve is green with a row of black hearts running along its length, similar to the left liripipe of his jester's hood. His left glove has a green trank with black fingers with a black heart on the back of the hand, while the right glove has a black trank with green fingers and a green heart on the back of the hand. Both gloves have claws.

Harlequin wears loose black trousers that have golden hearts halfway up the front of his thighs. He wears knee-high boots with flat soles. His left boot is green with a black collar, black laces, and a black sole. His right boot is black with a green collar, green laces, and a green sole.