• Director, Konkuk Univ. Hospital Healthcare Center
• Director, Alumni Association of Seoul National University
• Professor, the school of medicine, Konkuk University
• Board of Director, Suwon University
• Served as President, Korean Society of Gastroenterology
• Served as President, Korean Association for the Study of the Liver
• Served as Head Professor, Internal Medicine of Kyunghee Univ. Medical Center
• Served as Commentary Committee, KBS
• Served as Professor, the school of medicine, Korea University
• Served as Surgeon, Air Force
• Internship & Residency, Internal Medicine Dept., Seoul National University