Atsumu dyed his hair blond and has a dark undercut. Unlike his twin brother, Osamu, his hair is flipped to the right side. His eyebrows are dark brown, an indication of his original hair color. His brown eyes are large, hooded, and slightly drooping. He can usually be seen wearing a smile or smirk on his face. Outwardly, Atsumu appears to be a carefree, confident person who's usually seen with a lazy smile on his face, though he enjoys provoking people and giving offhand compliments.