Leslie Keith Gifford-Wood was born at Kirkby Ravensworth Grammar School, North Yorkshire, in 1892. He was the younger of two sons born to Rev. Robert Gifford-Wood, headmaster of the school and later vicar of East Cowton, and Caroline (née Rogers Martin). He was educated at Richmond Grammar School where he won a prize for languages, was a member of the cricket, football, and hockey teams, and won the school challenge shield for long-distance running. In 1913 Gifford-Wood was awarded both the Ellerton and Newby scholarships to study at Durham University, and matriculated in Michaelmas term of that year as a member of Hatfield Hall. He studied for a BA in Classical Honours, passing his first year exams at Easter 1914 with Class II Honours. While at university he played cricket, football and hockey for his college.
Gifford-Wood left his studies to enlist in a Royal Fusiliers Public Schools Battalion upon the outbreak of the war. From there he was gazetted on 16 September 1914 as a Temporary Second Lieutenant in the 6th Battalion of the Yorkshire Regiment (Green Howards). The Battalion underwent training at Belton Park near Grantham, then Witley Camp in Godalming, Surrey, before departing from Liverpool on the H.M.T. "Aquitania" on 3 July 1915. After a week-long journey, they landed at Mudros Bay on the Greek island of Lemnos on 10 July 1915. The Battalion first saw action on 6 and 7 August 1915 during the landing at Suvla Bay. Despite heavy casualties they were successful in securing the hill of Lala Baba and continued to advance to the east over the following days. On 22 August Gifford-Wood was in the leading party at the Battle of Scimitar Hill, but the British forces there suffered defeat, with Gifford-Wood, aged 22, among the heavy casualties. Although he was at first reported wounded and missing, his death was accepted by the War Office on 24 October that year, but an obituary was not published in The Times until February 1916. This reports,
"[h]e fell, shot in both legs, 600 yards south-east of Chocolate Hill, and is said to have been last seen falling into a Turkish trench."
Obituary, The Times, 22 February 1916, page 7, Issue 41096
His body was never identified, and he is therefore commemorated on the Helles Memorial in Gallipoli, as well as the East Cowton 1914-1918 war memorial. He is also commemorated on the Hatfield College 1914-1918 memorial plaque.