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 objective is to help my patients manage and maintain their physical and mental health. 

I truly enjoy working with and helping my patients to be their healthiest versions of themselves. I enjoy the long-term relationships that I have developed. it is important to me to take the time to listen, communicate, and build trust with my patients. 

Outside of work, I enjoy traveling, hiking, reading, lifting weights, and spending time with my friends and family.  

I am originally from Russia. I underwent undergraduate and medical school education in Texas, and moved to the Boston area for postgraduate training in 2001. 

I have practiced in Dorchester and Weymouth, Massachusetts since 2006. I joined South Shore Medical Center and South Shore Hospital in the Fall of 2017.

I am an experienced pulmonologist who provides care for multiple pulmonary diseases, including COPD, asthma, sarcoidosis, interstitial lung disease, lung nodules and lung cancer.