James William Jeffery was born in Lillingstone-Dayrell, Buckinghamshire, in 1876, son of George and Sarah Jeffery. The youngest of five children. His father George died in 1876, aged 34.
1881 Census records James aged 5, at school, living with his widowed mother, sisters, Mary 10, Fanny 9, brothers, Thomas 7 and George 6, in Chapel Green, Lillingstone-Dayrell, Bucks.
Nothing else is known about James until July 1895, when he enlisted in the Oxfordshire & Buckinghamshire Light Infantry with the service number 5076. (The Service Numbers 4993 to 5303 were issued between February 1895 and September 1896).
In 1912, James married Florence Hester Annie Bish, in Watford, the daughter of Charles William and Annie Bish. They had one son Arnold James Jeffery born in Farnham, Surrey, in August 1913.