My treatment philosophy is to establish good rapport with patients during their difficult moments, and to focus on shared decision-making while working on treatment plans and management of acute issues.

I have been practicing medicine for more than 20 years now. I like communicating with patients while focusing on their medical issues and helping formulate plans to meet the treatment needs. Apart from medicine, I enjoy spending time with my two boys, cooking and baking. I am an avid nature lover and enjoy hiking. Exploring new places brings me true happiness. Yoga and meditation helps me unwind after hectic days. 

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 exceptional care to hematology and oncology patients, and support patients and their families when they are at their most vulnerable. 

It is a privilege and an honor to have the opportunity to establish meaningful, long-term relationships with my patients and their families. I believe in open, honest communication and a patient-centered model when formulating a treatment plan. I look forward to supporting my patients not only physically, but mentally and emotionally as well. 

Outside of work, I enjoy spin classes, going to the beach, and spending time with family and friends. 

My mission is to guide and empower patients as active participants in their care to promote a healthy lifestyle and prevent disease throughout their lifespan.

As a Primary Care NP, having the ability to form lasting relationships with my patients is what I find especially unique and rewarding. I highly value a holistic approach to patient care, as I believe comprehensive health expands beyond the physical aspects. I want to work together with each patient, since more successful outcomes are achieved through a mutually agreed upon and individualized plan. I like to practice what I preach by living a healthy, active lifestyle outside of work that includes running, yoga, hiking, spending time with family and friends, and traveling.