Dr. Greenfield received a BBA in Finance from Baylor University in Waco, Texas and MD degree from the University of Texas Southwestern Medical School in Dallas, Texas. He completed a General Surgery residency at the Medical College of Virginia in Richmond, Virginia followed by a fellowship in Cardiothoracic Surgery, also the Medical College of Virginia. Dr. Greenfield then went on to complete a fellowship in Pediatric Cardiovascular Surgery at the Hospital for Sick Children in Toronto, Canada. He previously was on the full-time faculty at Tulane University Medical School in New Orleans, Louisiana and clinical faculty at Texas Tech University Medical School in Lubbock, Texas. Dr. Greenfield currently practices in Northeast Tennessee at Wellmont Holston Valley Medical Center in Kingsport, Tennessee and at the Mountain Home VA Medical Center in Johnson City, Tennessee. He also serves on the clinical faculty at the East Tennessee State University Quillen College of Medicine. He is certified by the American Board of Thoracic Surgery. Dr. Greenfield serves as the medical director for both the Cardiothoracic Surgery ICU and the Center for Wound Care and Hyperbaric Medicine at Wellmont Holston Valley Medical Center in Kingsport.