William Thomas Kerley was born in Sutton Waldron, Dorset, England in early 1884 and he was baptised on 14 April that same year.

He was the son of Charles Kerley (b. 1847) and Emma Caroline Pope (b. 1851), natives of Edmondsham, Dorset who had married on 5 June 1867 and who went on to have a total of nine children, with seven living past infancy. Their known children, besides William, were: Robert Charles (b. 1867), Frederic George (b. 1870), Ellen Jane (b. 1875), Ada Caroline (b. 1879), Charlotte Maud (b. 1881) and Rose Amelia (b. 1883).

William was born into an agricultural background and his father was an agricultural labourer. He first appears on the 1891 census living in St Michael, Gussage, Cranborne, Dorset. The following 1901 census sees William and his family living on Pentridge Farm, Pentridge, Cranborne. Aged 16, William had already left school and was working as a domestic footman. By the time of the 1911 census William had left home and was living as a footman at "The Hall," Farnborough, Banbury, Oxfordshire, the home of a wealthy man named Joshua Fielder. William's own parents were living in contrasting conditions in Woodmanton, Bower Chalke, Wiltshire, his father still farming.

When he signed-on to the Titanic, on 4 April 1912, William gave his address as Woodminton Cottages, Salisbury. The Titanic was his first ship. As a second class steward he received monthly wages of £3 15s.

Kerley, who was unmarried, died in the sinking. His body was one of the last recovered on 6 June 1912 by tanker SS Ottawa. His body was buried at sea.