James Wingate Johnston was born in Scotland c. 1804. He was a Graduate of the University of Glasgow (M.D. 1828).
He first came to Australia as Assistant Surgeon on the Sulphur, arriving at Swan River, Western Australia on 6 June 1829.
Three years later in correspondence to Governor Stirling dated 10 December 1832 from H.M.S. Sulphur he gave his favourable opinion of the climate of Swan River . While on the Sulphur a significant collection of plants, shells and minerals was made.
After a less than favourable report of the items taken back to England he made his feelings known:
Collections in Natural History brought home in H. M. S. Sulphur -
In perusing your Journal for last month, I was not a little astonished at observing, under the head of Portsmouth correspondence, a paragraph alluding to the specimens brought home under my charge in his Majesty's ship Sulphur - Botany, conchology, mineralogy, and zoology, not particularly well preserved. I must beg leave to differ from your correspondent, with the exception of the zoological, which, from many of them having been nearly three years on board, and for four months previous to their being landed having been in the hold, may easily account to any nautical man or collector for their not being in the most perfect state; as for the mineralogical and conchological part, I am at a loss to comprehend what is meant; but as for the botanical, by far the most valuable part of the collection, I may safely say, that it was certainly in that state that any botanist could have arranged and classified it with ease. My own collection, a very minor one, which was preserved in the same manner, I presented to my esteemed friend and late preceptor Dr. Hooker, Professor of Botany, Glasgow, who expressed his high approbation both as to their state of preservation and value as rare plants.
Mr. Editor, I should not have troubled you with these remarks, but in justice I consider myself bound to relieve the character of my much-valued friend, Mr. Collie, the indefatigable collector and preserver, from this unfounded imputation.
Your most obedient servant,
J. WINGATE Johnston, M. D., Late Surgeon of H.M.S. Sulphur.
92, Renfield-street, Glasgow, 13th Feb. 1833
Appointed Surgeon Royal Navy
James Wingate Johnston was appointed Surgeon in the Royal Navy on 27 June 1832. 
He was appointed Surgeon to the Dublin in 1841
He was employed as Surgeon Superintendent on two convict ship voyages to Australia:
Dr. James Wingate Johnston, retired Inspector-General of Hospitals and Fleets, who has been awarded the good service pension in the place of Dr. John Wilson, deceased, entered the Naval Medical Service as assistant-surgeon in 1825, and after serving in that capacity for upwards of six years on the North American and Home Stations, and on particular service, was promoted to the rank of surgeon in 1832, in which capacity he served with great credit on the North American, West Indian, South American, Pacific, and Home Stations, and also in charge of two convict-ships.
He was promoted to the rank of Deputy Inspector-General in 1847, and was employed as Deputy Inspector-General of the fleet under the command of the Earl Dundonald on the North American and West Indian Stations, and subsequently in the same capacity, for nearly four years; at Jamaica Hospital, during the prevalence of cholera and yellow fever, and afterwards at the Royal Naval Hospitals at Deal, Chatham, and Greenwich.
He was promoted to the rank of Inspector-General in 1864, and his name was placed on the retired list in November, 1868.
Sir Gilbert Blane Medal
The Standard announced that James W. Johnston was the recipient of this prestigious award - We have great pleasure in stating that, at the annual award of Sir Gilbert Blane's gold medal, the successful competitors for the honour were James Wingate Johnston, M.D., deputy inspector of hospitals in the West Indies, and Thomas Russell Dunn, M.D. 
James W. Johnston was appointed to Deal Hospital in 1854 
Honorary Surgeon to the Queen
Appointed Honorary Surgeon to the Queen in May 1859 - Navy List
In the 1861 Census James W. Johnston age 55 is recorded residing at Royal Melville Hospital, Chatham, Kent, with his wife Christiana Blackhall Denham Kidd, age 33. Christiana gave her birth place as Nova Scotia. Three children resided with them - Wingate Kidd age 7, Christiana age 6 and Alexander J.J. aged 4. They had three servants. James gave his occupation as Physician, M.D. of Glasgow University, Deputy Inspector-General Royal Navy.
In the 1871 Census his occupation was the same. His son Wingate age 17 was a student of medicine. Son Alexander was not in their household on the night of the census
In 1871 the good service pension of 100 pounds per annum, vacated by the death of Dr. John Wilson was awarded to James Wingate Johnston, retired. 
By the time of the 1881 Census he was retired and resided with his wife and daughter at Clarenden Road East, Annandale, Portsea.
James Wingate Johnston died 17th October, 1882
We regret to announce the death of Inspector-General James Wingate Johnston, M.D., Honorary Surgeon to the Queen, which took place yesterday at his residence, Annandale, Clarendon Road, Southsea. The deceased officer was the senior Inspector-General of the Navy. He entered the Service in 1825 and attained his present rank on the 21st March 1864. he was in receipt of a good service pension and also held the Blane medal. The deceased was most popular in the Service, and was generally respected by all who knew him. He was in the 78th year of his age, had been ailing for some months past, and had been attended by Dr. J. Ward Cousins, of Southsea. The funeral will take place at the Cemetery Highland road, Southsea on Friday afternoon.