 On August 15, 2008 he won a gold medal at the +100 kg category of the Beijing 2008 Summer Olympics.On 30 April 2011 Ishii returned to Judo to compete in the United States Championship in the open division; he won all the matches, securing the gold medal.After winning the gold medal, Ishii expressed his wishes to apply his talents in the sport of mixed martial arts (MMA) to the dismay of the Japanese Judo Federation.