He is an Adjunct Lecturer to both undergraduates and postgraduates in NUS, and an Adjunct Associate Professor with International Medical University Malaysia. He is also currently the Chairman of the Chapter of Prosthodontists, College of Dental Surgeons.
Dr Leong has been an executive committee member of the Prosthodontic Society (Singapore) since 2008 and he served as President from 2010 to 2012. He was an abstract writer/reviewer for the International Journal of Prosthodontics and has made presentations at conferences in Australia,China, Indonesia, Myanmar, Malaysia and Singapore and has published in scientific journals both in Singapore and internationally.