He is trained in "lucha libre" and "technical" styles of professional wrestling, spending the majority of his career in Japan and Mexico. He is credited with inventing the "Asai Moonsault."
He made his American debut in 1996 for the now defunct World Championship Wrestling. He suffered an arm injury in 1999 that required surgery that was botched causing nerve damage. It was thought this would be the end of his career and he announced his retirement.
That same year, he opened a promotion and training school call Toryumon, training several wrestlers in his style.
In 2002, he had another surgery to repair the damage done to his arm and returned to wrestling in his promotion. In the Spring of 2003, he signed with WWE.
He is one of the most gifted wrestlers that professional wrestling has ever seen, as he can adapt to any style and be effective at it.