MRCS LRCP 1905.
Leonard studied medicine at University College London and Sheffield. He held resident appointments at Sheffield Royal Infirmary, including senior house physician and pathologist in charge of the skin department. Leonard served as a captain in the RAMC and was a specialist in venereology and consultant dermatologist to Manchester Military Hospitals. Leonard settled in Chorlton-cum-Hardy, near Manchester, but also had consulting rooms in St Ann's Square. He was relief medical officer for Manchester and Salford Lock Hospital, and assistant school medical officer for Manchester. Leonard was a member of MMS and Sheffield Medico-Chirurgical Society. He died as a result of an accident on 15 September 1932, aged fifty two.