Following the opening of his family practice in New Brunswick he served as president of the College of Physicians and Surgeons and the New Brunswick Medical Society before being appointed to the Premier's Council on Health Strategy.

Elected to the New Brunswick legislature in 1999, he served two years as Minister of Health and Wellness and Community Services, then two years as Minister of Education. He returned to his medical practice in 2003 and two years later was named to the CFB Gagetown Agent Orange herbicide spray investigation. He later was appointed chair of the province's Trauma System Advisory Committee, and served on the Premier's Round Table on Sustainability. In 2011 he became chair of a Provincial Committee on Health Services.

Dr. Furlong has been a physician member and preceptor for the McGill-Dalhousie medical program, a lecturer for the University of New Brunswick Nursing Faculty, and a Canadian faculty member for the United Kingdom King's Fund Health Care Leadership Program.
 
He is a Rotary International Paul Harris Fellow, recipient of the New Brunswick Medical Society Order of Merit, received an Honorary Doctor of Laws from The University of New Brunswick in 2008 and is a CMA Senior Member. An accomplished athlete, he not only has won gold at the Canadian Senior Games, but has also won an NRC grant to research and develop a ground contact monitoring device for Olympic race walking.
 
He was also awarded the national Sir Charles Tupper Award, recognizing physicians who demonstrate exemplary leadership, commitment and dedication to the cause of advancing the policies, views and goals of the Canadian Medical Association at the federal level.
 
A published author, Medicare Myths - 50 Myths We've endured about the Canadian Health Care System, Dr Furlong continues to actively promote solutions to New Brunswick's and Canada's health care challenges.