A graduate of the Massachusetts Institute of Technology, Dr. Payson received his Doctor of Medicine (MD) degree at Dartmouth Medical School after which he practiced as a primary care physician. During this period, Dr. Payson worked in the public health service providing care at a Native American Reservation.

While practicing as a physician, Dr. Payson was active as a physician leader and became medical director and CEO of a large multi-specialty medical group. Dr. Payson then co-founded and served as CEO of a physician-sponsored health plan, Healthsource, which became publicly traded and reached fifteen states with three million members. After the sale of Healthsource to Cigna Corporation, Dr. Payson led the dramatically successful turnaround of Oxford Health Plans, greater New York City's largest health plan. After Oxford, Dr. Payson was engaged in successfully transforming other large health care companies including private equity sponsored enterprises.

Dr. Payson has been a mentor in the Dartmouth Medical School and Tuck School combined MD-MBA Program and a graduate student lecturer at Dartmouth, the Columbia University Mailman School of Public Health and the University of Chicago Booth School of Business. Dr. Payson is on the Board of Directors of several charitable or educational institutions including the City of Hope, a tertiary cancer hospital and research center; Medicine in Need, a charitable Gates Grand Challenge awarded biotechnology company and the Dartmouth Medical School, Board of Overseers.