Haruhi was forced to Mitmachen the host club to pay for a vace she broke but she can't be a host as a girl so she kreuz dresses and only the club members knows he is a she.
Sadly (Because Tamaki-sama and Haruhi-kun could've made great Yaoi.), Haruhi (The main character) is a girl. She cut her hair because some dude put gum in her hair, and she got used to looking like a boy.