Leong won the Asian Tourqualifying school in 2006, and after a poor debut season won again in 2007. His 2008 form was much improved, and he claimed his first tour win at the Worldwide Selangor Masters. Since then he has played on the Asian Tour full-time, with a best Order of Merit finish of 25th in 2008.
*Note: The 2017 PGM Northport Championship was shortened to 54 holes due to weather. 1Co-sanctioned by the PGA Tour of Indonesia 2Co-sanctioned by the Asian Development Tour