Known best for his two-year term as president of the American Atheists organization, Buckner also held executive positions with the Council for Secular Humanism and the Atlanta Freethought Society.
He earned a bachelor's degree from Rice University and a doctorate from Georgia State University.
He contributed to several publications, including Kimberley Blaker's Fundamentals of Extremism: The Christian Right in America and Tom Flynn's The New Encyclopedia of Unbelief.
He grew up in Fitzgerald, Georgia, as the son of an Episcopal minister. His marriage to Lois Bright resulted in a son named Michael.
When Georgia Republican governor Sonny Perdue organized a rain prayer event during a 2007 drought, Buckner and his Atlanta-based organization staged a protest against something that they believed violated the doctrine of separation of church and state.