Sriyantha was a champion athlete during his school days at Nalanda College Colombo in the late 1980s.

Sriyantha Dissanayake won a silver and a bronze medal in the 1990 Asian Games in Beijing and brought pride to Sri Lanka.

In addition, he gained two more gold medals and a silver in the 1993 South Asian Games in Dhaka.

Sriyantha also represented Sri Lanka in athletics at the 1992 Summer Olympics held in Barcelona, Spain.

He is arguably the best male sprinter to come from his island being the only Sri Lankan athlete to have won a 100-metre medal in the Asian games.