He is the world's most wanted thief. Yet he takes it upon himself to foil other criminals engaged in more serious crimes because he is a gentleman thief, if there's ever such a thing. He sometimes seem incompetent but that's just a charade to throw his opponents off guard. While he has been arrested and thrown in jail a couple of times, he has never remained there for long. His infatuation with Fujiko Mine is perhaps his biggest weakness (isn't that common with all men, thinking with their other head?) and it often lands him in undesirable (compromising?) situations.
His weapon of choice, the Walter P38 pistol.