Prof Lee is a practicing senior consultant paediatrician of the paediatric endocrinology service at the Khoo Teck Puat-National University Children’s Medical Institute, National University Hospital, and also a tenured professor of the Yong Long Lin School of Medicine, National University of Singapore. He was the head of department of Paediatrics, National University of Singapore (1 Apr 2017-30 Sep 20225), the president (2020-2022) of the Asia Pacific Paediatric Endocrine Society (APPES), and the president (2021-2023) of the College of Paediatrics and Child Health, Academy of Medicine, Singapore.

His clinical and research interest is in obesity, diabetes, and growth. His research is focused on obesity, insulin resistance, and mediators of obesity related morbidities. His research approach to elucidate the biological susceptibility to human obesity and related morbidities is three pronged, by studying the 1) genetics, 2) In-utero and early life developmental factors (developmental origins of health and disease), and 3) role of gut microbiome. He has also research interest in engineering probiotics to confer health benefits and disease treatment. His other clinical research also encompasses various paediatric endocrine disorders. He has more than 270 publications in local and international journals (as of Nov 2025).

In the recent years, Prof Lee has focused his efforts on the developing programmes and strategies to advance child and maternal health, promoting healthy living for families, and improving health equity through his leadership role at the National University Centre for Women and Children.