Dr Nares Smitasin is a graduate of the Faculty of Medicine, Siriraj Hospital, Mahidol University, Thailand. After graduation, he worked as an intern at the Yala Regional Hospital, Thailand.

He completed the Internal Medicine Training at the University of Hawaii, and Infectious Diseases Training at the University of Illinois, Chicago, USA. Dr Nares Smitasin obtained both the American Board of Internal Medicine and Infectious Diseases. After 5 years of training in USA, he returned to Bangkok, Thailand where he worked as an Infectious Diseases Consultant at Bumrungrad International Hospital for one year before joining NUH.