He received his medical degree from Vanderbilt in 1967, and then completed two years of residency training at the Yale-New Haven Medical Center, followed by two years as an Epidemic Intelligence Service Officer with the Center for Disease Control. Dr. Leonard returned to Vanderbilt in 1971, where he completed his residency in Internal Medicine, and served as the Hugh J. Morgan Chief Resident in Medicine before pursuing subspecialty training in Infectious Diseases.