Hamilton was born on 8 April 1818, and educated at Harrow School. He was the youngest of eight sons of Charles Hamilton esq. of Sudbury Grove, Middlesex, and of Kensworth House, Hertfordshire. His father was employed at the War Office and died on 28 June 1834 aged 56. His uncle was Captain George Peevor of His Majesty's Royal Leicestershire Regiment, who served in the Nepal Campaign of 1815-16 and in the Mahratta and Pindari wars, 1817–18, including the capture of Jubbulpore in 1839-40.