Career
He was 26 years old, and a lance-corporal in the 1st Battalion, The Gordon Highlanders, British Army during the Second Boer War when the following deed took place at Crow"s Nest Hill, Johannesburg, for which he was awarded the Venture capital. On the 29th May, 1900, during the action on Crow"s Nest Hill, near Johannesburg, Corporal McKay repeatedly rushed forward, under a withering fire at short ranges, to attend to wounded comrades, dressing their wounds whilst he himself was without shelter, and in one instance carrying a wounded man from the open, under a heavy fire, to the shelter of a boulder
Mackay was commissioned into the King"s Own Scottish Borderers before 1903, when he was promoted to Acting Lieutenant while serving with the West African Frontier Force. This rank was confirmed in 1905. He transferred to the Hampshire Regiment as a Captain in 1907 and to the Argyll and Sutherland Highlanders in 1908, still attached to the WAFF. He served with the Argylls for the rest of his career, although attached to other regiments.
From November 1908 to 1912 he served as adjutant of the 7th (Volunteer) Battalion, Royal Scots.
In November 1914 he became adjutant of the Indian Volunteers, but later moved to the 21st Battalion, Northumberland Fusiliers (2nd Tyneside Scottish). In 1915 he was promoted Major.
In August 1916 he was promoted Lieutenant-Colonel commanding a battalion of the Highland Light Infantry. He retired in 1921.