Greenfield is a diplomate of the American Board of Orthopedic Surgery, the Arthroscopy Board of North America, and the American Academy of Pain Management. Greenfield is the medical director of the Miracle Mile Outpatient Surgery Center in Los Angeles and the Los Angeles Stem Cell Institute, a team physician for a local high school, and a medical evaluator for industrial injuries in the State of California. He is on the faculty of the physicians assistant training program at the University of Southern California Medical School. Greenfield has published research and clinical practice articles in medical journals, and he has lectured on orthopedic medicine and surgery and the management of chronic intractable pain in the United States and Mexico. Greenblatt also holds an MBA degree, is a Certified Public Accountant.