From her physical appearance, Haruka is almost indistinguishable from a boy. But, by adding to this fact that she acts like a boy by driving around on her motorcycle compounds the confusion of those who don't know her particularly well.
Also, Haruka prefers to wear the male school uniform. For many girls, Haruka appears to be a handsome boy. However, when the Inner Scouts get crushes on her, Haruka teases them plentifully, especially after they find out that she is really a girl.
As Sailor Uranus, she takes a more serious turn. She is utterly devoted to her mission, and is willing to sacrifice her and her partner's life ( Although she cares for Michiru greatly ) if it would save the universe. She also possesses the first talisman; the Space Sword.