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.

My mission is to provide comprehensive care and holistic support to patients throughout their cancer journey.

With over a decade of service in healthcare, I have expertise in clinical practice, research, and patient-centered care. I earned my Doctor of Nursing Practice degree from UMASS Worcester. My experience ranges across inpatient and outpatient settings, including hematology, oncology, clinical research, medical/surgical care, and primary care.  Outside work, I enjoy sailing and spending time with my family including our dog Una. 

I strive to build a space where patients feel safe to discuss their health concerns and engage in shared decision-making.

Prior to joining South Shore Health, I had the privilege to train at UMass Family Medicine Residency and complete an additional year of fellowship to also care for patients living with HIV/viral hepatitis at the Family Health Center of Worcester.

Outside of work, I love spending time with my family, running, gardening, and camping/hiking.