[3] Keyes served in the Tirah Expedition in 1897–1898, attached to the 2nd Battalion, King's Own Scottish Borderers, where he was slightly wounded in the hand by a splinter and hit by a spent bullet in the chest at the Battle of Chagru Kotal on 18 October 1897.
He served in the Russian Civil War in 1919–1920, serving as Brigadier-General General Staff South Russia and Army of the Black Sea from December 1919 to June 1920,[13][14] and being mentioned in despatches three times and appointed Companion of the Order of St Michael and St George (CMG) in November 1919.
He retired from the army in May 1932 with the honorary rank of brigadier-general,[18] and the following year returned to England to live at Freezeland Farm, near Ninfield, Sussex.
He was appointed Knight Commander of the Order of the Indian Empire (KCIE) shortly before his retirement from the IPS in the 1933 New Year Honours.
Keyes was a committed Christian and a supporter of the Oxford Group and its principles of "moral rearmament", as well as an active freemason.