[1] He was the eldest surviving son of Captain John Wynne, Royal Horse Artillery, of Wynnestay, Roebuck, County Dublin, by his wife, Anne, daughter of Admiral Sir Samuel Warren.

[3] On 2 December 1878 he embarked in command of the 2nd Field Company of the Royal Engineers for Natal, part of the small number of reinforcements sent to the colony ahead of the Anglo-Zulu War of 1879.

Following his arrival at Durban Wynne marched to join the first column as commanding Royal Engineer under Colonel (afterwards Sir) Charles Knight Pearson at the mouth of the Tugela River.

There, in the presence of the enemy Wynne with his company of Royal Engineers, assisted by the line, laid out and built Fort Tenedos on the left bank of the Lower Tugela.

Wynne had been working to improve the drift to facilitate further crossings but upon hearing the action commence had his men drop their shovels and take up arms to serve as light infantry.

[8] Wynne was tireless in laying down ranges, repairing approaches, or cutting down bush, always resourceful and cheerful, making the best of the means at hand; largely because of his skill and exertions the defence was a success.

[3] On one occasion, Wynne found that marker posts, used by the garrison to determine rifle ranges in case of attack and to delineate the route of a new approach road, were being moved at night by the Zulu.

On the relief of Ekowe he was moved in a cart to the Tugela River,[3] where, promoted brevet major a week before, he died at Fort Pearson on 9 April 1879, his 36th birthday.