He was employed as Surgeon Superintendent on the emigrant ship Orestes from Bristol in 1839.
British Medical Directory for 1853, Melville Royal Naval Hospital Chatham -
M.R.C.S. Edinburgh 1822;
M.D. St. Andrew's 1851;
Surgeon R.N; Surgeon Melville Royal Naval Hospital, Chatham; received the 'Blane' Gold medal for the most approved Medical Report whilst serving in H.M.S. 'Eagle' on the south east coast of South America 1845-46-47.
Medical Register 1865 -
Deputy Inspector General R.N. Hospital, Haslar, Gosport, Hants. Qualifications -
Lic. Royal College Surgeons, Edinburgh 1822.
M.D. University St. Andrews 1851.
Member Royal College Physicians London 1850.
Sir Gilbert Blane Medal
Sir Gilbert Blane, Bart., with the concurrence of the Lords Commissioners of the Admiralty, for the encouragement of Naval Medical Science, and excitement of an emulation that may conduce to the interests of an important branch of the public service, established a Fund in perpetuity, for the purpose of providing the means of conferring a gold medal, once in every two years, on such two Medical Officers, whether Surgeons or Assistant-Surgeons acting as Surgeons, as shall produce the most approved journals of their practice, whilst actually serving in Her Majesty's Ships. - Peter Leonard on the list of Medical Officers who have received Sir Gilbert Blane's Gold Medal 
Author of Records of a Voyage to the Western Coast of Africa in H.M.S. Dryad, and of the Service on that Station for the suppression of the Slave Trade, in the years 1830-31-32. 
Peter Leonard and Mr. Sloggett appointed Inspectors and Visiting Surgeons of certified hospitals under the Contagious Diseases Prevention Act. 
Inspector-General of Hospitals and Fleets
Appointed to the position 24 March 1871 
Naval Medical Service
The Lancet published the details of some of Peter Leonard's duties and achievements in 1871 when he was granted a Navy Pension -
We record with great satisfaction that the three Greenwich Hospital Pensions for naval medical officers, created by the Order in Council of March 24th last, have been granted severally to Dr. Peter Leonard, inspector-general, and Drs. John Dunlop and A. C. Macleroy, surgeons in the navy.
We referred to this subject on February 4th and 11th last, and there can be no doubt that much good has been done by ventilating the existence of grievances in the service, and showing the modes whereby they may be remedied.
The grant of a pension to Dr. Leonard is a just and proper recognition of valuable services rendered under peculiar and difficult circumstances. A large item of the success that attended the first application of the Contagious Diseases Act to the Royal Navy is due to the assiduous exertions of this officer, who entered the service half a century ago, has served more than twenty years afloat, and has sailed round the world four times. In these days of rigid economy, when efficiency and everything else are sacrificed to reduction of expenditure, it is a very significant fact that the energy of the Medical Director-General of the Navy has obtained from My Lords, in the matter of pensions, that kind of even-handed justice which alone can make the Royal Naval Service popular, or other than a refuge for the destitute. 
Peter Leonard, R.N., can be found in the 1871 Census. He resided at 'Plaisance', Croydon, Surrey, age 68. Birthplace Scotland; Occupation Medical Inspector of the General Hospital. His wife Ann age 65, also born in Scotland and their 7 years old grandson Frederick Duke lived with him. The family employed a cook and a housemaid.