I strive to provide excellent care to my patients and to help them understand their conditions through education.

As a rheumatologist, my goal is to take care of my patients as individuals and to work together with them to find the most effective treatment plan. I am passionate about helping patients with rheumatologic conditions find relief with the therapies we have available today. Outside of work, I enjoy playing tennis, exploring new restaurants, and spending time with family and friends.

My mission is to give the same care to my patients as I would want for my family or myself.    

I was born and raised in the Boston area.  After a long period of schooling and training across the country (New Hampshire, Ohio, California, Pennsylvania), I have been honored to return home to take good care of my people!  When not fixing retinas, I enjoy spending time outdoors with my wife and three children.   

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 treat my patients with compassion and kindness and take the time to know and understand them.

I am certified by the American Board of Internal Medicine in Internal Medicine, Medical Oncology and Hematology. I received my BA in Biology at State University of New York at Buffalo and my MD from Jefferson Medical College of Thomas Jefferson University in Philadelphia, PA. I did my residency in Medicine at Lankenau Hospital in Philadelphia, PA and Fellowship in Hematology-Oncology at University of Connecticut Health Center in Farmington, CT. I was recognized in Boston Magazine's 2017 Top Doctors list. Outside of work, I enjoy listening to classical music, traveling, running, and bicycling.