William was the son of Thomas and Elizabeth Hemsley. Thomas and Elizabeth had ten children of whom only eight were still living at the time of the 1911 census; William, Thomas, Emma, Warren, Harry, Hilda, Clara and George.
The family was living at 10 Turton Street, Bulwell, when William joined the Grenadier Guards in 1906. According to William's service record his brother Thomas was serving in the Notts and Derby Regiment (Sherwood Foresters) at the time William enlisted.
By the time of the 1911 census William's parents were living at 172 North Gate, New Basford, Nottingham. His father was a labourer in a bleaching works. Only six of Thomas and Elizabeth's children were in the household on the night of the census; Emma (19), Warren (16), Harry (11), Hilda (9), Clara (4) and George (1).
The same year William (24), who had joined the Army Reserve in 1909 on completion of his period of engagement, was a police constable. He was a boarder in the household of John William Brunt and his wife Carrie at 20 Welbeck Street, Mansfield, Nottinghamshire. John and Carrie had two children, Elsie (12) and Willie (11) and also had another boarder, James Acker (30), an insurance agent.
William married Hilda Cooper, a spinster, at Hyson Green Parish church, Nottingham, on 28 December 1913. Their daughter, Lillie Maud, was born the following year on 20 August 1914.
In 1920 when Hilda completed a form giving the names of William's surviving blood relatives she was living with her daughter at 67 Parliament Street, Nottingham, although the family had lived previously on Chatsworth Road, Nottingham. At this time, William's parents and his siblings with the exception of Emma were living at 166 North Gate, New Basford. Emma was married (Roper) and living at 7 Plimsoll Street, Hyson Green, Nottingham.