He served as adjutant of the 1st battalion from 21 January 1899 and throughout the Second Boer War (1899–1902), when the battalion was posted to South Africa. They were part of the force sent to relieve the siege of Kimberley, and saw action at the Battle of Magersfontein in December 1899, where Gordon was wounded. He then served in the Orange Free State from February to May 1900, and took part in the battles of Paardeberg (February 1900), Poplar Grove, Driefontein (March 1900), Hontnek, Vet River and Hand River. Transferring to Transvaal, the battalion was again in action at Doornkop in May 1900, where they suffered severe losses, then took part in the battles of Belfast and Lydenburg (August 1900).[3] The battalion stayed in South Africa throughout the war, which ended with the Peace of Vereeniging in June 1902. Four months later 475 officers and men of the 1st battalion left Cape Town on the SS Salamis in late September 1902, arriving at Southampton in late October, when the battalion was posted to Glasgow.[4]
On the 11th July, 1900, during the action near Leehoehoek (or Doornbosch Fontein), near Krugersdorp, a party of men, accompanied by Captains Younger and Allan, having succeeded in dragging an artillery waggon under cover when its horses were unable to do so by reason of the heavy and accurate fire of the enemy, Captain Gordon called for volunteers to go out with him to try to bring in one of the guns. He went out alone to the nearest gun under a heavy fire, and with the greatest coolness fastened a drag-rope to the gun and then beckoned to the men, who immediately doubled out to join him in accordance with his previous instructions. While moving the gun, Captain Younger and three men were hit. Seeing that further attempts would only result in further casualties, Captain Gordon ordered the remainder of the party under cover of the kopje again, and, having seen the wounded safely away, himself retired. Captain Gordon's conduct, under a particularly heavy and most! accurate fire at only 850 yards range, was most admirable, and his manner of handling his men most masterly; his devotion on every occasion that his Battalion has been under fire has been remarkable.[5]