Born in Guernsey and educated in Jersey,[1] De Lisle was, after graduating from the Royal Military College at Sandhurst, commissioned into the 2nd Battalion of the Durham Light Infantry (DLI) in March 1883.

After the outbreak of the Second Boer War in late 1899, he was appointed in command of the Australian Brigade, with the local rank of lieutenant colonel from 30 January 1900.

[13][14] In a despatch dated 23 June 1902, Lord Kitchener, who had been commander-in-chief (C-in-C) during the latter part of the war, described De Lisle as "an officer of remarkable force of character.

"[15] For his service he was appointed a Companion of the Order of the Bath (CB) on 21 August 1902,[16] and received the actual decoration from King Edward VII at Buckingham Palace on 24 October 1902.

[19][20] De Lisle was appointed second-in-command of the 1st (Royal) Dragoons in 1903 and then became commanding officer (CO) of the regiment in 1906,[2] after being promoted to lieutenant colonel in February.

[36] De Lisle was made colonel of his old regiment, the Durham Light Infantry, in October 1928, in succession to Major General Sir Frederick Robb.