Dr. Tan is a Geriatrician attending both at Johns Hopkins Hospital and the Johns Hopkins Bayview Medical Center. Dr. Tan is a Co-Investigator and Co-Director of Recruitment for the Baltimore Experience Corps® Study, a NIH funded Randomized Controlled Trial of the health effects of an older adult volunteer program in the Baltimore Public School System. He is the principle investigator of an Older Americans Independence Center Pilot Project investigating the effect of Experience Corps participation on physical Activity. He is currently a member of the American Geriatrics Society Public Policy Committee. Dr. Tan’s current research interests include older adult civic engagement, social marketing, physical activity, social capital, and productive aging.

Prior to joining the faculty at Johns Hopkins, Dr. Tan was selected as a White House Fellow 2003-4, where he served as a Special Assistant to the Secretary of Veterans Affairs. Dr. Tan also completed the UCSF/ San Francisco General Hospital (SFGH) Primary Care Internal Medicine Residency Program, served as a Geriatrics and VA National Quality Scholars Fellow at the Veteran's Affairs Medical Center at UCSF, and has published on health disparities. Dr. Dr. Tan received a B.A. from Brown University where he participated in the Tougaloo College Exchange Program and studied for a semester at an historically black college in Jackson, Mississippi. He was commissioned as a 2nd Lieutenant from Providence College ROTC, where he was a Distinguished Military Graduate, and graduated from New York University School of Medicine as a member of the Alpha Omega Alpha honor society.

Previously, Dr. Tan served as an Assistant Clinical Professor of Medicine at the University of California, San Francisco (UCSF), where he received a Geriatric Academic Career Award.

Dr. Tan received the Jeffrey Weingarten Award from UCSF for "the compassionate care of patients and the practice of medicine according to the highest ethical standards".