Walter Humphrey was born in Wrotham during 1886, one of ten children of a farm bailiff from Wateringbury named William, and his wife, Emily Driver. In 1891, when Walter was five, his family lived on the Ightham Road at Fen Pond Cottage, and it seems likely Walter attended the local school in Ightham. Ten years later the Humphreys had moved to Basted and were resident in Platt at the time of the 1911 census, by which time Walter had left school and was working with his older brother Harry on the railway as platelayers.

At the time war started on 4 August 1914 the family were living in the village at Forest Villas. Like many other young men in Platt, Walter was enthused with patriotic duty and rushed to enlist the same month in Sevenoaks where he joined the Royal Engineers and attached to the 112th Railway Company, which was a unit that specifically recruited platelayers. Sapper Humphreys was sent to Longmoor for training and embarked in Southampton for Le Havre on board the SS Duchess of Argyle at 5:30 pm on 15 February 1915.

By the start of May, the company is known to have been working on the railway line between Abele and Poperinge however, unfortunately, the unit War Diary between the end of July 1915, (when Walter would have found himself based at Peselhoek), and the period leading up to his death on 21 January 1916, has not survived. Consequently, the exact circumstances of his death are unknown. Official records have him dying of accidental injuries and his body buried in the Beauval Communal Cemetery near Amiens.