Regimental Sergeant-Major William Mitchell attested for the Rifle Brigade at Cambridge in October 1857, aged 19 years. Advanced to Corporal in August 1859, Sergeant in October 1861 and Colour-Sergeant in May 1866, he was present in the Jowaki operations of 1877-78, in addition to those of the Second Afghan War, when, as a recently promoted Regimental Sergeant-Major, he fought at Ali Musjid. His last appearance in the Regimental Muster Roll is dated April 1881, under the heading 'Embarked for England', but the Afghanistan Medal Roll lists him as 'Dead'.