[3][4] Other issues during his term included a national discussion on end of life care [5] (that coincided with a Supreme Court of Canada ruling that struck down the ban on medical aid in dying (MAID)[6] and new legislation allowing MAID),[7] as well as issues around the public health implications and possible medicinal utility of cannabis.

[8] Simpson served as the Chair [9] of the Wait Time Alliance [10] – a federation of 18 national medical and surgical specialty societies, the Canadian College of Family Physicians and the Canadian Medical Association that monitored and published report cards on the state of medical wait times in Canada.

[15] Currently, he serves as Executive Vice President (Medical) and Chief Medical Officer at Ontario Health - the Crown agency that oversees the health care system in Ontario.

He is a Professor in the Department of Medicine and in the School of Policy Studies at Queen's University and completed a 10-year term as Chief of Cardiology and medical director of the Cardiac Programs at Kingston General Hospital and Hotel Dieu Hospital in 2016.

His clinical and research interests include health policy (particularly access to care, wait times, seniors' care and health human resources), medical fitness to drive, catheter ablation, atrial fibrillation, inherited heart rhythm diseases, cardiac resynchronization therapy, and leadless pacemaker technology.