Cleckley was born in Augusta, Georgia, and graduated from the Academy of Richmond County in 1921. He was graduated in 1924 summa cum laude with a Bachelor of Science degree from the University of Georgia (UGA) in Athens where he was a member of the varsity football and track and field teams. Cleckley won a Rhodes Scholarship and graduated from Oxford University with a Bachelor of Arts in 1926. Robert D. Hare devised the "Psychopathy Checklist (PCL)" to assess the main characteristics of psychopathic behavior, based in part on Cleckley's work.