He gave up his ordinary school life and decided to "become a delinquent from today on" (thus the title of this manga), after moving to his new home in Chiba. To make his appearance more noticeable, he dyed his hair blond (he often use this appearance to pretend to be a foreigner).
Being a very athletic person, he used his talent for the sole purpose of brawling and actually becomes a real delinquent. His fighting style is based around his speed, as he often dodges most attacks, becoming enraged whenever he is forced to block.
Despite being the most self-centered person in the series and may seem stupid or shallow at first, he actually cares about his friends.
(Source: Wikipedia)
