Born at Comber, County Down, in 1883, to Arthur Hughes De Wind and his wife, Margaret Jane, Edmund was educated at Campbell College, Belfast (entered in 1895, number 249).
He chose banking as his profession and worked at the Bank of Ireland's Clones branch.
De Wind moved to Canada in 1911 and joined the Canadian Bank of Commerce, Edmonton, when the 1st World War began.
He served with The Queen's Own Rifles of Canada for a period of six months prior to his enlistment as a private, in 1914, in the Canadian Overseas Expeditionary Force; arrived in France with the 2nd Division of CEF in September, 1915; saw action in the Battle of the Somme (1916) and at Vimy Ridge (1917).
De Wind earned a commission in September, 1917, in the 15th Battalion, The Royal Irish Rifles.
His citation reads:
For most conspicuous bravery and self-sacrifice on the 21st March, 1918, at the Race Course Redoubt, near Grugies. For seven hours he held this most important post, and though twice wounded and practically single-handed, he maintained his position until another section could be got to his help.The first memorial to de Wind is a pillar his mother caused to be carved at the main entrance on the west front of St Anne's Cathedral, Belfast.
On two occasions, with two NCOs only, he got out on top under heavy machine gun and rifle fire, and cleared the enemy out of the trench, killing many. He continued to repel attack after attack until he was mortally wounded and collapsed.
His valour, self-sacrifice and example were of the highest order.''
The west front was dedicated to the men from Northern Ireland who died in the Great War. It was dedicated in 1927.
2nd Lieutenant De Wind is also named on Poziers Monument; Mount de Wind, Alberta, Canada; a housing estate in his home town of Comber, County Down, is also named in his honour.
A plaque memorial was erected in his old school, Campbell College, Belfast.