I enjoy taking care of my patients and including their families and the entire treatment team in the process. 

I have had the pleasure of practicing in surgical specialties in community-based hospitals over the last several years. I love working in community hospitals because it is small enough to give patients personalized care but also large enough to provide the best specialized care. Outside of work, I enjoy baking, taking care of my chickens and hiking.

My philosophy is to always take the time to listen to the patient's concerns and do my best to address them.

I look forward to helping patients and members of our community navigate unexpected and stressful health events with extra attention to the patient and their most immediate loved ones, family, and friends. 

I look forward to providing care and service to the community that my wife and I have called home since 2010. We have two beautiful children who lovingly occupy the majority of our free time when not providing healthcare at South Shore Health. 

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.

The root of the word “doctor” originated from the latin word docere, which means to teach. My philosophy as a doctor is to teach and educate my patients on their conditions and general health.

I love to learn and, therefore, I chose being a doctor as my profession. Being a physician means a life time of learning about diseases and medicine, but more importantly, I get to learn the story behind each of my patients.

Outside of work, I love to learn to sail, and flying. I am also an avid rock climber, hiker, and traveler.

My mission is to teach patients how better health habits can prevent many diseases.  

It is a privilege to help people and establish long-term relationships with my patients. I believe that everyone's medical care should be individually tailored. We all have unique characteristics that need to be considered when deciding a treatment plan. Communication is paramount. Outside of work, I love rock climbing and surfing; however, most importantly I love spending time with my family.

My aim is to empower patients with shared, informed decision-making.

I feel grateful to work in medicine every day, and to develop relationships with my patients that empower them to feel informed and comfortable with their treatment plans. I particularly value the importance of taking time to discuss goals of care with my patients. Outside of work, I am an avid reader, and my hobbies include writing, jogging, and spending time with my significant other and out cat, Soot

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.

Dr. O'Brien is Medical Director of Maternal-Fetal Medicine at South Shore Health. 

As a Maternal-Fetal Medicine physician, I am dedicated to caring for women and families navigating high-risk and medically complex pregnancies with expertise, compassion, and individualized attention. 

I strive to integrate evidence-based medicine with a holistic approach that recognizes the physical, emotional, and social factors that shape each patient’s experience. 

I am also committed to advocating for equitable healthcare and improving access and outcomes for marginalized and underserved communities.

My career started in the US Army and it was a privilege to serve and care for women in the military and their family members while training at Walter Reed Army Medical Center and then stationed overseas in Germany for 4 years. I returned to the South Shore area since this is home and have been been fortunate to raise my family and to practice here since 2002. I am so grateful to have the opportunity to care for the women in our community. Although I transitioned to a more administrative role, I continue to practice obstetrics and gynecology here in the hospital and will continue to strive to offer the best care to patients through open communication and strong relationships.