Sirisanont began swimming at age seven, despite that he did not like the sport much at first. Admittedly, he had some breathing problems while jumping off into the water. In 1991, Sirisanont was selected to the Thai national team at his first Southeast Asian Games in Manila, where he won six medals (four golds and two bronze). His name was reached towards an early sport popularity, when he broke SEA Games records in three different events.