As the Medical Director of Addiction Medicine at South Shore Health, I work to tackle the defining medical challenge of our time: Substance use and alcohol use disorder.

In addition to seeing adult patients at South Shore Hospital, I work with colleagues across South Shore Health to develop and implement a comprehensive addiction medicine treatment program. This program will connect patients with the resources they need to manage substance use disorder, no matter if they come to us through the Emergency Department, primary care, or another setting. Additionally, I serve as Medical Director for Spectrum Health System's opioid treatment program, ATS/detox, CSS, and therapeutic community in Weymouth.

Prior to my work at South Shore Health, I helped launch the Bridge Clinic at Boston Medical Center, which connected patients with treatment options for substance use disorder. I also served as Medical Director for Spectrum Health Systems’ Opioid Treatment Program in Weymouth.

In my spare time, I enjoy baseball, reading fiction, snowboarding, and cooking.

Having grown up on the South Shore, it is a pleasure to care for patients of this region. I served in the US Navy following medical school and completed my surgical training through the Navy. Following multiple military assignments, I chose to return to the area in order to serve my local community and reside closer to my family. 

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.

I graduated from Colegio Nacional de San Isidro in Buenos Aires, Argentina and completed my medical degree at Buenos Aires University School of Medicine. My surgical and urological residency were spent at the Hospital Italiano in Buenos Aires. I was an attending Urologist at Hospital Roffo in Buenos Aires until I came to the United States. At that point I was a Urology Fellow working on a research project at the Children’s Hospital and Harvard Medical School in Boston. I completed his American residencies in urology and surgery at the University of Massachusetts.

I enjoy spending time with my wife and three children.

My mission is to provide compassionate and effective care to treat patients in critical moments in order to ensure the best possible outcomes through prompt intervention and evidence-based practices.

I completed residency at Boston Medical Center. I believe in providing evidence-based and compassionate care at all times and in honest and open communication with my patients about their condition and treatment. Outside of work, I enjoy rock climbing and spending time outdoors and with my family.

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.

It is a privilege to treat patients compassionately in our community. I strive for excellence, open communication, accessibility, and long-term relationships. Outside of work, I especially love spending time with my family, swimming, bicycling, tennis, golf, sailing, photography, and magic.

I provide comprehensive care to vascular patients. This ranges from the treatment of peripheral arterial disease, venous insufficiency and aneurysms, as well as hemo dialysis access.

I also have advanced wound care certification, as well as a board certification in Hyperbaric Oxygen Therapy.

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. 

I enjoy traveling to difference parts of the country and sampling unique cultures and cuisine. Having grown up in the Boston area, I enjoy watching sports with the local teams, and playing golf.