Mabry, a native of Tallahassee, Florida, was the son of former Florida Supreme Court Justice Milton H. Mabry and Ella Dale Bramlett. He went on to become an airship pilot and captain in the United States Army Air Service. Captain Mabry died piloting the Army airship Roma, a dirigible he was testing, when it crashed in Norfolk, Virginia on February 21, 1922. The event marked the greatest disaster in American aeronautics up to that time, resulting in 34 deaths. Mabry was laid to rest at Arlington National Cemetery. He was survived by a brother, G. E. Mabry, of Tampa, Florida.