Dr.Duffy graduated with a degree in physiology, magna cum laude and Phi Beta Kappa, from the University of Minnesota in Minneapolis, where he also completed his medical education. His residency training was in Internal Medicine at Cedars-Sinai Medical Center in Los Angeles, during which time he also received a Solomon Scholars Resident Research Award.

Dr. Duffy established his Beverly Hills private practice in General Internal Medicine in 1989, where he continues to practice today. His practice emphasis is in Preventive Medicine and the early detection and prevention of coronary artery and vascular disease. The association with Westside Medical Imaging allows a unique opportunity to use the latest technology diagnosis and treat these disease processes before they become clinically relevant. Dr. Duffy has served as an active attending physician at Cedars-Sinai Medical Center where he has been involved with the training of resident and has had patient care in virtually every service. He has been requested to provide consultative medical services by numerous colleagues and medical staff.