Dr. MacKenzie is the Fred and Julie Soper Professor and Chair of the Department of Health Policy and Management of the Johns Hopkins Bloomberg School of Public Health.  She is a graduate of the School of Public Health where she earned Master of Science and doctoral degrees in biostatistics. She joined the Hopkins faculty in 1980 and holds joint appointments in the School's Department of Biostatistics and with the departments of Emergency Medicine and Physical Medicine and Rehabilitation at the Johns Hopkins University School of Medicine. In addition to her faculty appointments, Dr. MacKenzie served as Senior Associate Dean at the School from 1996 to 2000 and Director of the Center for Injury Research and Policy from 1995-2005. Dr. MacKenzie completed a term as chair of the National Advisory Committee for Injury Prevention and Control and is currently President of the American Trauma Society.

Dr. MacKenzie's research focuses on the impact of health services and policies on the short- and long-term consequences of traumatic injury. She has contributed to the development and evaluation of tools for measuring both the severity and outcome of injury, which have been used to evaluate the organization, financing and performance of trauma care and rehabilitation. Of particular interest to Dr. MacKenzie is the delineation of factors (both medical and non-medical) that explain variations in functional outcome. Her research has advanced the knowledge of the economic and social impact of injuries and the understanding of how personal and environmental factors influence recovery and return to work. Dr. MacKenzie's ongoing research includes a national evaluation of the cost and effectiveness of trauma care and efforts to develop and evaluate self management programs for people living with a disability.

Her awards include the A.J. Mirkin Service Award from the Association for the Advancement of Automotive Medicine, the Ann Doner Vaughan Kappa Delta Award from the American Academy of Orthopaedic Surgeons, the Distinguished Career Award from the American Public Health Association (Injury Control and Emergency Health Services Section) and the American Trauma Society's Distinguished Achievement Award. She is also an honorary fellow of the American Association for the Surgery of Trauma.