He served with Sir Garnet Wolseley on the Red River Expedition in Canada in 1870, retiring from the army the next year.

Dalton was approximately 46 years old, and an acting assistant commissary in the Commissariat and Transport Department (later Royal Army Service Corps), British Army during the Anglo-Zulu War when he was awarded the VC for his actions on 22 January 1879, at Rorke's Drift, Natal, South Africa.

His citation in the London Gazette of 17 November 1879 reads: For his conspicuous gallantry during the attack on Rorke's Drift post by the Zulus on the night of the 22nd January 1879, when he actively superintended the work of the defence, and was amongst the foremost of those who received the first attack at the corner of the hospital, where the deadliness of his fire did great execution, and the mad rush of the Zulus met with its first check, and where, by his cool courage, he saved the life of a man of the Army Hospital Corps, by shooting the Zulu who having seized the muzzle of the man's rifle, was in the act of assegaing (thrusting an assegai into) him.

This officer, to whose energy much of the defence of the place was due, was severely wounded during the contest, but still continued to give the same example of cool courage.

He is buried in the Russell Road Roman Catholic Cemetery with a memorial, Plot E. The precise location of his grave is 33° 57' 37" S 25° 36' 53" E. The barracks in Haverfordwest, Pembrokeshire, is named "The Dalton VC Centre" after him.