When the Anglo-Zulu War began the 22-year-old veteran was made a corporal in the Natal Native Contingent of the British Army in South Africa.

[1] On 22 January 1879, at Rorke's Drift, Natal, Corporal Schiess, in spite of suffering from bad blisters on his foot caused by ill fitting boots, displayed great gallantry when the garrison had retired to the inner line of defence and the Zulus had occupied the wall of mealie bags which had been abandoned.

Schiess was the first man serving with a locally raised native unit to receive the Victoria Cross, the "British-only" rule being broken under political pressure, also being the first Swiss national to do so.

[citation needed] The citation for Schiess's Victoria Cross was given as: For conspicuous gallantry in the defence of Rorke's Drift Post on the night of the 22nd January, 1879, when, in spite of his having been wounded in the foot a few days previously, he greatly distinguished himself when the Garrison were repulsing, with the bayonet, a series of desperate assaults made by the Zulus, and displayed great activity and devoted gallantry throughout the defence.

[6] In the 1964 film Zulu, Dickie Owen portrays Schiess as a much older soldier than he was during the Battle of Rorke's Drift.