Dr. Mackey has been director of the AHEC-NE since 1981. AHECs function as the primary rural educational outreach arm of UAMS. The northeast Arkansas center provides more than 200 hours of continuing medical education per year to health professionals in the region. During Dr. Mackey's tenure, approximately 90 residents in family practice have completed the residency program at the center. More than 90 percent of these physicians practice in Arkansas.

Dr. Mackey is a past president of the Arkansas Caduceus Club, the organization of alumni of the UAMS College of Medicine, and is a member of the American College of Physicians, the Arkansas Medical Society, the American Society of Nephrology, the Renal Physicians Association, among other professional organizations.

Dr. Mackey has served in various leadership capacities at St. Bernard's Medical Center in Jonesboro, including as chairman of the Department of Medicine. He is a former president and current board member of the NEA Clinic (formerly the Northeast Arkansas Internal Medicine Clinic). He has also served on the Advisory Board of the Arkansas State University School of Nursing, as well as on the Board of Directors of the Jonesboro Helpline. He has been an active reviewer for Postgraduate Medicine, Aviation Space & Environmental Medicine, and Southern Medical Journal.

The Southern Medical Association is a multispecialty medical association governed by an elected physician council. The mission of the association is to enable physicians to practice the highest standards of medicine by fostering professional development and economic stability through education, services, collegiality, and leadership across multiple specialties.