Schoomaker completed his internship and residency in internal medicine at Duke University Medical Center in Durham, North Carolina, from 1976 to 1978, followed by a fellowship in hematology at Duke University Medical Center in 1979. He is certified by the American Board of Internal Medicine in both internal medicine and hematology. His military education includes completion of the Combat Care Casualty Course, Medical Management of Chemical Casualty Care Course, AMEDD Officer Advanced Course, Command and General Staff College, and the U.S. Army War College.