Hamilton was a great nephew of General Sir George Pollock who led the Army of Retribution in the First Afghan War.

Hamilton was 22 years old, and a lieutenant in the Staff Corps and Corps of Guides, Indian Army during the Second Afghan War when the following deed took place on 2 April 1879 at Futtehabad, Afghanistan, for which he was awarded the VC: For conspicuous gallantry during the action at Futtehabad on the 2nd April, 1879, in leading on the Guide Cavalry in a charge against very superior numbers of the enemy, and particularly at a critical moment when his Commanding Officer (Major Wigram Battye) fell, Lieutenant Hamilton, then the only Officer left with the Regiment, assumed command and cheered on his men to avenge Major Battye's death.

He commanded a small force of 20 Cavalry and 50 Infantry, all from the Corps of Guides, which formed an escort for Sir Louis Cavagnari the Envoy who was to set up the Residency in Kabul following the Treaty of Gandamak.

There was a change of heart when the Secretary of State for India, Lord Cranbrook, noted that Hamilton's actions were similar to those of Captain John Cook and Lieutenant Reginald Hart who had both been awarded the Victoria Cross two months earlier.

[3] A slightly over-life-size statue of Hamilton striding over an Afghan threatening him with a knife was produced in bronze-painted plaster by Charles Bell Birch in Dublin in around 1880.