Dr. MacCumber completed an AB at Princeton University and an MD and PhD in Neurosciences at the Johns Hopkins University School of Medicine. He served as a resident and the Assistant Chief of Service at the Wilmer Eye Institute. His retina training was under Robert Machemer, MD at the Duke University Eye Center when he received the Heed Fellowship and the Ronald G. Michels Fellowship. In 1996, Dr. MacCumber joined Illinois Retina Associates and Rush University Medical Center, where he now holds the positions of Professor and Associate Chairman for Research for the Department of Ophthalmology.

He has been very active in organized ophthalmology. He completed the American Academy of Ophthalmology (AAO) Leadership Development Program, has served as the delegate to the American Medical Association and as a councilor to the AAO Council both from the American Society of Retina Specialists (ASRS). He completed a six-year term on the Board of Directors of the Macular Society as Website Chair and served on the Board of Directors of the ASRS. He is currently serving as the Chair of the AAO Council and a member of the AAO Board of Trustees and as the Past-President of the Chicago Ophthalmological Society.