Alexander Stewart was born on 20 February 1793, the fifth child and second son of James Charles Stewart and his wife Margaret nee Menzies. His elder sister Elizabeth (1789‐ 1859) married William Tindell in 1815. 
Alexander Stewart entered the Royal Navy on 4 May 1812.
He served as Assistant-Surgeon on the Royal Navy ships Seahorse, Madagascar, and Glasgow between 1812‐16.
He was awarded a Naval General Service Medal for his part in the bombardment of Algiers on 27 August 1816 whilst serving aboard the HMS Glasgow. On 16 September 1816 he was promoted to rank of Naval Surgeon.
In the 1820's he served on HMS Bann, patrolling at Gibraltar and off the Cape Coast. In 1825 he was transferred to the HMS Pyramus. 
SURGEON SUPERINTENDENT CONVICT SHIPS
Alexander Stewart was employed as Surgeon-Superintendent on three convict ship voyages to Australia:
America to NSW in 1829.
Southworth to Van Diemen's Land in 1830
Aurora to NSW in 1833.
SURGEON SUPERINTENDENT EMIGRANT SHIPS
Woodbridge to NSW in 1838. He was remunerated £200 for his employment on the Woodbridge
Adam Lodge to NSW in 1840.
Although he continued to travel, Alexander Stewart settled his family in the Illawarra district of New South Wales
An Old House By Arthur Cousins -
This is one of a number of articles written by Mr. A. Cousens who is well-known for his writings on the history of the South Coast. He is the author of the book "The Garden of New South Wales," an authorative historical narrative of the settlement of the Illawarra District. In his article he describes the building of Minnamurra House which he believes is the oldest house In South Illawarra.......
Unfortunately there are no records to say exactly when, or by whom Minnamurra House was built. But it is practically certain that Dr. Robert Menzies, very soon after establishing his temporary home, commenced to build a permanent one. At the first big land sale of Kiama township in 1840, Dr. Alexander Stewart, Dr. Menzies' uncle, bought an allotment of land in Shoalhaven Street, next to that bought by Michael Hindmarsh on which Mr. Hindmarsh erected a building to be used next year as Kiama's first post office under the charge of George Hindmarsh, Michael's brother.
Dr. Stewart, medical officer of the Royal Navy, continued for many years to travel to and from New South Wales, and later brought his mother and sister to "Minnamurra" and had a cottage built for them, a cottage later removed to the village of Jamberoo where it still is. But before that, in 1843, Mrs. Menzies' sister arrived at "Minnamurra" to live there.
Like so many of the early houses of Illawarra it is a large two storey building with lofty and large rooms, and a very wide staircase. 
Dr. Alexander Stewart died at Minamurra Farm on 28 November 1855,
 Michael Organ and Arthur Cousins, The Menzies Family of Minamurra House, Jamberoo, Illawarra Historical Publications, 1994.
 Kiama Independent (NSW : 1947 - 1954) Wed 14 May 1952 Page 4 AN OLD HOUSE