Population health concerns the total well-being of whole communities, countries and the world, in contrast to the individualised focus on patients in the other branches of clinical medicine. This applied field of study is inherently interdisciplinary, drawing on the sciences of epidemiology, biostatistics and mathematics as well as the social sciences of economics, politics and leadership.

Professor Gabriel Leung is the fortieth Dean of Medicine, and Chair of Public Health Medicine at The University of Hong Kong (HKU). Professor Leung currently holds the Helen and Francis Zimmern Professorship in Population Health. He is a clinician and the last Head of Community Medicine at HKU as well as Hong Kong's first Under Secretary for Food and Health and fifth Director of the Chief Executive's Office.

A specialist in public health medicine, Professor Leung's work revolves around topics that have major population health impact locally, where Hong Kong is a reliable and unique epidemiologic sentinel for China, or where the SAR is best placed to address the fundamental science at hand globally.

Professor Leung established and has directed the University's Infectious Disease Epidemiology Group since the 2003 SARS epidemic and led the government's efforts against the pandemic H1N1 in 2009. He continues to co-head HKU's World Health Organization (WHO) Collaborating Centre for Infectious Disease Epidemiology and Control. Current priorities are investigating influenza, hand-foot-and-mouth disease, human papilloma virus and other infections of public health significance. His team is recognised as one of the world's leading epidemiologic laboratories in influenza research.

In parallel, Professor Leung leads several large-scale longitudinal cohorts, tracking tens of thousands of lives to study the fundamental causes of non-communicable conditions and to explain the health impacts of contemporary social phenomena.

A final strand of his work concerns the economics and policy issues of health systems. His team is the government's health accountant and projects health care human resources needs into the future. Regionally, Professor Leung has tirelessly worked to build capacity throughout the Asia Pacific. He served as inaugural Chair of the Asia Pacific Observatory on Health Systems Policies (2010-14).

After reading medicine at the University of Western Ontario, he completed his family medicine residency training in Toronto. He earned his Master's degree from Harvard University and research doctorate from HKU.

Professor Leung advises national and international agencies including WHO, the China CDC and the Asian Development Bank. He was Vice President and Censor in Public Health Medicine of the Hong Kong College of Community Medicine. He is an Adjunct Professor of the University of Pennsylvania and Peking Union Medical College, as well as Adjunct Professorial Researcher of the China National Health Development Research Center. He edited the Journal of Public Health (2007-14) and was co-editor/associate editor for Epidemics and Health Policy. He currently serves on the editorial boards of six journals, including the British Medical Journal.