Loving horses, In 1897 he raised the
1st Australian Volunteer Horse Regiment, and he was elevated
lieutenant colonel in 1898. His military force was captured in two poems by Scottish-Australian poet
Will H. Ogilvie (1869–1963), in
The Real Mackays! (1898) and
Your Chance, Mackays! (1899). In 1895 he was elected to the
New South Wales Legislative Assembly as the member for
Boorowa, serving until 1899, when he was appointed to the
Legislative Council. Mackay served as
Vice-President of the Executive Council and
Representative of the Government in the Legislative Council in the
Lyne ministry from September 1899 to April 1900, when he left to serve in the
Boer War until 1901, commanding the 6th Imperial
Bushmen's contingent of New South Wales. He saw action at
Elands River, was
mentioned in despatches, and made a
Companion of the Order of the Bath (CB). Mackay was awarded the
South African War Medal with four clasps, He returned from South Africa in July 1901. He resumed his former position of Vice President of the Executive Council and Representative of the Government in the Legislative Council in 1903 as part of the
See ministry, serving until 1904. He continued to serve in the Legislative Council until 1934 when the council was reformed by members indirectly elected by the Parliament. Considered too old, he was not appointed to active service overseas in
World War I. He was appointed to conduct an inquiry into the
Liverpool riot of 1916 by soldiers at the
Liverpool and
Casula camps. In 1920 he was promoted
brigadier general and later retired as a
major general. He was appointed an
Officer of the Order of the British Empire on his retirement. ==Writings==