After graduating from Seoul National University's medical school, he obtained qualifications as a specialist in family medicine, preventive medicine, and occupational environmental medicine.

He is head of the Public Health Service Division at Seoul National University Hospital, currently working as a professor of preventive medicine at Seoul National University College of Medicine.

He teaches students the subject "Human, Social and Medical" and has published books “The Origin of Diseases” and “The Changing Era of Diseases”; they have been translated into English and published abroad.

He has published more than 300 papers in international journals, and he is currently a member of the Korean Academy of Medicine and the Korean Academy of Science and Technology, and also a member of the WHO policy advisory committee of the World Health Organization.