I started practicing primary care at Boston Medical Center in 2001 and was part of the Faculty of Boston University's School of Medicine. In 2010, I transitioned to the Quincy and Braintree area to continue serving as a primary care physician and urgent care provider. I graduated from the University of Puerto Rico School of Medicine and completed my residency in Internal Medicine at the Hospital of Saint Raphael/Yale-New Haven Hospital.

My mission is to provide excellent care to all of those in need with compassion and empathy.

I grew up in Duxbury, MA on the South Shore and attended Colby College in Maine. I then obtained my Master of Science degree at Mercer University School of Medicine in Georgia. After securing those credentials I attended MGH Institute of Health Professions for PA school, where I graduated in 2021. I take pride in getting to know each patient, their specific medical condition and then guiding them through difficult medical pathways and stressful circumstances. I enjoy my work/life balance and love traveling, workout classes, skiing, and everything wellness.

I grew up on the South Shore and attended Holy Cross for college where my concentration was pre-medical sciences and sleep research. During summers in college I worked as an EMT and following college I worked in a collaborative Brigham and Women’s Hospital/Harvard Medical School lab studying allergy and asthma. While at the University of Massachusetts Medical School and Lahey Clinic my focus was on primary care internal medicine. In 2006 I was the recipient of the “Patient Care Award” which is Lahey Clinic’s highest physician honor. I joined South Shore Medical Center in 2006.

My treatment philosophy is to help educate individuals on their role in disease prevention and develop relationships with patients—working as a team to manage both chronic and acute health issues. I believe that each individual has their own unique set of circumstances that influence their health and working together to overcome barriers is an essential part of providing healthcare. I consider it a privilege getting to know patients and families and always look at the big picture when caring for individuals. Outside of work I love spending time with my family, going to the beach, gardening and hiking. I am teaching myself how to ice skate so I can play hockey with my boys! 

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.