Naoki Matsudo won his first race at age six, at a pocket-bike event in Japan back in 1979. He then progressed through the Kanto Road Race Championship, the SUGO Championship and the Japan A Class GP 250 series. In 1999 he lifted the 250cc All Japan Championship with 5 race wins and, having made several wildcard Grand Prix appearances including a podium finish at Suzuka in 1998, he was offered the chance at a World Championship ride in 2000 with Petronas Sprinta Team TVK. It proved to be a shrewd move as Matsudo collected 79 points and finished 10th in the final standings. He contested the 250 class for 4 more years, after which he made two MotoGP wild card appearances while working as a test rider for Kawasaki.