In the early 1880s Hamilton travelled to
India with his regiment, and there was involved in the
Burma Expedition from 1886 to 1888, remaining in the country as
adjutant of his regiment from 1886 to 1890 and winning the campaign medal with two clasps. He was promoted to
captain in December 1890 and attended the
Staff College, Camberley, from 1892–93. By 1896 he was back in England, and was appointed an
aide-de-camp to Major-General
Thomas Kelly-Kenny, commanding an infantry brigade at
Aldershot Garrison. In the following year, Hamilton was involved in the
Mahdist War, when he accompanied Major General
Sir Herbert Kitchener's army against the Mahdist forces, fighting at the
battle of Atbara, the
battle of Omdurman and, in November 1899 as
deputy adjutant general (DAG), in the final advance against the
Khalifa during the
Battle of Umm Diwaykarat. He was
mentioned in dispatches (5 September 1898) and rewarded for his service with the
Distinguished Service Order (DSO) and the
Imperial Ottoman Order (Fourth Class) from the
Khedive of Egypt. In late 1899 Hamilton left Egypt and was immediately engaged in another war, against the
Boers in South Africa, where he was again appointed aide-de-camp to Major-General Kelly-Kenny, by now commander of the
6th Division. From January 1900 he was a staff officer with the role of deputy assistant adjutant-general, and performed so well in this position that he was advanced to assistant adjutant-general in July 1900 and recommended to Lord Kitchener as a personal aide-de-camp and military secretary from November 1900. He was engaged in operations in the
Orange Free State,
Transvaal and
Cape Colony and also saw action at the
battle of Paardeberg, for which he was mentioned in dispatches three times (31 March 1900, 16 April 1901, 29 July 1902) and awarded the
Queen's South Africa Medal with four clasps and
King's South Africa Medal with two clasps. For his field service, he was appointed aide-de-camp to the King, and given a
brevet promotion to
colonel. With the war's successful conclusion, Hamilton returned home in June 1902, carrying the peace despatches from Lord Kitchener to the government and the King, who received him at Windsor Castle. Less than six months later, Hamilton accompanied Kitchener to India, again as his military secretary, and received the substantive rank of colonel on 28 November 1902. In February 1906 he left Kitchener's service and returned to England to assume command of the
7th Infantry Brigade, and with it came the temporary rank of brigadier general, He was made a
Companion of the Order of the Bath (CB) in June. In October 1908 Hamilton left the 7th Brigade for a temporary promotion to
major general and an appointment as chief of the general staff in the
Mediterranean, in succession to Major General
John Maxwell. In April 1909 he was made a
Commander of the Royal Victorian Order (CVO). In June his rank of major general became substantive. His last peacetime appointment was in England, taking over from Brigadier General
Hugh Archdale the role of
general officer commanding (GOC) of the
North Midland Division of the
Territorial Force (TF) from January 1911. Hamilton relinquished this assignment and then received command of the
3rd Division, which his brother Bruce had commanded a decade earlier, from Major General
Sir Henry Rawlinson in June 1914, in the last weeks of peace before the
First World War. It would be his final command. ==First World War==