Su-ho has a tall and athletic build that reflects his background in mixed martial arts and street fighting. His toned physique is the result of years of physical training, though he doesn't flaunt it—his strength becomes evident only when he fights. He usually sports a relaxed and casual look, often wearing his school uniform slightly undone or paired with a hoodie or jacket, giving off an effortlessly cool vibe. His hair is typically styled in a messy yet stylish cut, which adds to his youth.