President Position:
Professor, Department of Internal Medicine, Yonsei University College of Medicine, Seoul, Korea
Director, Yonsei Liver Center, Severance Hospital, Yonsei University College of Medicine, Seoul, Korea 
Director, Human Resources Headquaters, Yonsei University Health System, Seoul, Republic of Korea 
Director, Administration of Yonsei University Health System, Seoul, Republic of Korea (2020-2021)
Director, Planning and Management Headquarter, Severance Hospital, Yonsei University Health System, Seoul, Republic of Korea (2018-2020)
 
Overseas Working Experiences:
2001-2003: Postdoctoral Fellowship, Liver Research Center, Brown Medical School, Providence, RI, USA.
2008-2009: Visiting Professor, WHO Collaborating Centres for Virus Reference and Research, Victorian Infectious Diseases Reference Laboratory (VIDRL), Melbourne Health, North Melbourne, Australia
 
Key Academic Society Activities:
Chairman of Academic Committee: The Korean Liver Cancer Association (2010-2011) 
Chairman of Academic Committee: The Asia-Pacific Primary Liver Cancer Expert Meeting (APPLE, 2013) 
Chairman of Academic Committee: The Korean Association of the Study of Liver (KASL, 2018-2019)
Chairman of Academic Committee: The Asia Pacific Association of the Study of Liver (APASL, 2022)
Secretary General: The Korean Association of the Study of Liver (KASL, 2022-Present)
 
Government Advisory Activities:
Consultant for health authority organizations in KOREA: The Ministry of Health and Welfare; the Ministry of Food and Drug Safety (FDA); Centers for Disease Control and Prevention (CDC), National Evidence-based healthcare Collaborating Agency (NECA)
 
Lecturer and Consultant for Global Companies:
Global: BMS, Gilead Sciences, Janssen, AbbVie, Roche, Assembly Biosciences, Arbutus, Brii, Vaccitech, GSK, Inovio, Aligos, Vir Biotechnology 
Domestic: SL Vaxigen, GeneOne Life Science, GreenCross, Yuhan, Samil and Ildong, etc
 
Editors of Scientific Journals:
Deputy Editor: Journal of Gastroenterology and Hepatology (2010-Present)
Associate Editor: Gut and Liver (2017-Present), Hepatology International (2019-Present), Clinical and Molecular Hepatology (2020-Present), PLoS ONE (2011-2017).
Editorial Board: Hepatology (2019-2021), Journal of Hepatology (2014-2019), Liver International (2013-Present), Scientific Reports (2019-Present) 
Referee: New England Journal of Medicine (2014-Present) and more than 30 journals
 
Social Activities:
Columnist: a columnist and writes “the comfortable liver world” in The Health Kyunghang (daily newpaper)
Honorable Doctors: he was selected as a honorable doctor in the Media (EBS 2017, 2019, 2020: The Chosun Media 2017). His biography has been accepted into Marquis Who's Who, which is comprised of the top 3% of the professionals in the world (2018).
 
Major Research Interests: 
Viral hepatitis B and C: Molecular biology, Clinical trials for new drugs
Liver fibrosis and liver cancer: Pathogenesis and treatment
 
Key Academic Activities:
80+ outstanding clinical trials as a principal investigator
400+ SCI(E) publications including original and review articles in the top class journal worldwide
130+ Invited overseas lectures around the world