Dr. Brian J. Yun graduated with an MD and MBA from Tufts University School of Medicine, where he was also named to the AOA Honor Society. After finishing his residency at the Brigham and Women's Hospital and Massachusetts General Hospital Harvard Affiliated Emergency Medicine Residency program, Dr. Yun completed an Emergency Department Administration Fellowship at MGH and also received an MPH in Clinical Effectiveness from the Harvard T.H. Chan School of Public Health. Thereafter, he stayed on as a faculty member at MGH. He is board certified in emergency medicine and is an Assistant Professor of Emergency Medicine at Harvard Medical School.

He is the Medical Director of the Emergency Department Observation Unit. His hospital leadership roles include serving as a Physician Advisor to Case Management and as a Capacity Physician. As a Physician Advisor to Case Management he serves as the link between case management and medical staff by providing on-going education about the rules of reimbursement, working as a member of the Utilization Review Committee, and providing MD-to-MD consultation to help remove barriers to transitions of care. In his role as a Capacity Physician, he addresses both the daily and systematic capacity challenges related to hospital transfers and patient placement challenges, physician communication issues, and barriers to patient progress of care.