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.

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.

I grew up in a small town in Northern New York, and joined South Shore Hospital and Brigham and Women's Hospital in 2012. I completed my undergraduate and medical education as well as my general surgical training and surgical critical care fellowship at the University of Rochester in Rochester, NY. I am also fellowship trained in minimally invasive and bariatric surgery from Dartmouth Hitchcock Medical Center. I have had a long-standing passion in bariatric and weight-loss surgery and my goal in joining the South Shore Hospital team was to bring that expertise and opportunity to the South Shore community. The hospital has been very supportive in this endeavor and over the past few years we have created a collaborative team of providers from across institutions to start the South Shore Hospital Center for Metabolic and Bariatric Surgery. As medical director it has been my pleasure to help the program grow into a strong clinical component  of the department of surgery and create more outreach into the community. I am also actively engaged as a trauma surgeon and have a busy general surgery practice taking care of a variety of disease processes including the minimally invasive management of gallbladder disease, hernia, GERD, hiatal hernias, as well as the surgical management of a variety of other gastrointestinal disorders. When I am not working, I enjoy the simple things in life like relaxing by a large campfire or spending the day at the beach with my family. 

My goal is to provide compassionate and equitable medical care to patients seeking care for breast-related concerns, including but not limited to breast lumps, abnormal screening mammograms, benign breast masses, and previous or current breast cancer diagnoses. 

I am a graduate of the Tufts University School of Medicine Physician Assistant and Masters in Public Health dual degree program. I have been working at the Dana-Farber Cancer Institute/Brigham & Women’s Hospital Division of Breast Surgery since June 2021.

It is my priority to provide care to patients that is skilled and supportive. I strive to accommodate a patient’s unique and individual needs such that all patients feel cared for and well-informed. I have professional interests in patient-oriented outcomes research and have studied coping and psychosocial wellbeing among adolescents and young adults with cancer. I am originally from Western Massachusetts, and my hobbies include hiking, skiing, and spending with family, friends, and my dog.