William Tollefsen, MD is the EMS and MIH Medical Director for South Shore Health. Dual-boarded in Emergency Medicine and EMS Medicine, Dr. Tollefsen works clinically as an Emergency Physician at South Shore Health in addition to his role as EMS Medical Director.

One of few physicians in the country to receive the prestigious "FAEMS" recognition, Dr. Tollefsen is also the Medical Director for OEMS Region IV, serving 61 cities and towns of the Metro-Boston EMS Council. As the current EMS Medical Director for eight municipal and three private ambulance services on the South Shore, Dr. Tollefsen interacts and provides oversight for over 400 Paramedics.

Dr. Tollefsen graduated from New York Medical College and completed residency training in Emergency Medicine at Harvard University, Brigham and Women's, and Massachusetts General Hospital. He completed a fellowship in Emergency Medical Services and Critical Care Transport at the University of Massachusetts, where he worked as an Emergency Physician and Flight Physician for UMASS LifeFlight. He completed an MBA at the Isenberg School of Management at UMASS Amherst, and holds a Master of Medical Science degree from the Boston University School of Medicine.

A former pre-hospital provider, he is actively involved in EMS system design, paramedic education and Critical Care Transport Systems. He works closely with multiple EMS, Fire and Law Enforcement agencies throughout Massachusetts.

His research interests include systems of care, resuscitation, airway management, and paramedic education.

Having grown up on the South Shore, it is a pleasure to care for patients of this region. I served in the US Navy following medical school and completed my surgical training through the Navy. Following multiple military assignments, I chose to return to the area in order to serve my local community and reside closer to my family. 

I'm a Senior Network Physician practicing at Dana-Farber Community Cancer Care in Weymouth. I am certified by the American Board of Internal Medicine in Hematology, Medical Oncology and Hospice and Palliative Medicine.  I received my BA from Oberlin College and my MD from Tufts University School of Medicine.  I did my training in Internal Medicine at Boston City Hospital and her Hematology-Oncology training at New England Medical Center. In my free time, I enjoy traveling, music and outdoor pursuits.