Bachelor in Medicine and Surgery, National University Singapore, 1991. Master in Medicine, National University Singapore, 1997.
Lecturer National University of Singapore, 1998—1999, assistant professor, since 1999. Registrar National University Hospital, 1998—2001, associate consultant, since 2001. Captain Singapore Armed Forces, 1994-1996.
Member of Singapore Society Immunology, Allergy and Rheumatology, National Arthritis Foundation.
Married Cheng Lai Fun. Children: Yoon Yi-An, Yoon Yi-Liang.