Jack Hepworth was born at home at Croft House, Moorgate, Rotherham, Yorkshire on 1st August 1911. He was the first of three children of Dr. Arthur Hepworth (1879-1944) and Hilda (1883-1965), née Jackson.  Arthur Hepworth was the son of a Dewsbury woollen mill owner and blanket manufacturer, Benjamin George Hepworth (1853-1928).
Jack in 1912 with his grandfather Benjamin G. Hepworth and his father F. Arthur Hepworth.
Arthur's younger brother Herbert R. Hepworth (1880-1958) was the father of the sculptor Barbara Hepworth (1903-1975).  Barbara was thus Jack's first cousin and was eight years his senior.
Arthur Hepworth had trained as a surgeon and had moved from Yorkshire in 1919 to Saffron Walden where he took up general practice and helped to run the local hospital, undertaking his own surgery. Jack's mother had been a hospital nurse before she married.

Jack's parents were keen on amateur dramatics, and were collectors in a small way of fine furniture. Some of this was stolen from Jack in a burglary while he was visiting his wife in hospital during her last illness in 1996.
Jack greatly enjoyed accompanying his father in his car on his home visits as a GP around the nearby villages. He was allowed to go out with the local gamekeeper at Audley End and learnt some country ways.
Saffron Walden Hospital c. 1940
The development of Jack's political views was no doubt influenced by his experiences in Saffron Walden, observing the inequities in the way the country people lived and the difficulties of the poor when sick, and witnesssing his father's anger at the behaviour of life insurance companies who refused the claims of the poor on technicalities.  These must have been reinforced by the impact of the Great War, in which his mother's dearest and youngest brother, Ken, was lost, and by the political and economic developments of the 1920s and 1930s. Jack became a committed communist during the 1930s and although, like many others, he was disillusioned by Stalin's implementation of a communist society and shocked by Russia's suppression of the Hungarian uprising in 1956-7, he nonetheless retained a socialist outlook throughout his life.
Saffron Walden Hospital c. 1940
Saffron Walden Hospital c. 1940
Jack with his parents and his sisters Jill and Peggy
Jack with his uncle Ken Jackson, who was killed on 30th October 1917, the fifth day of the 16-day second battle of Passchendaele.
Jack's mother Hilda C. Hepworth neé Jackson c. 1910
Jack's parents drawn by Barbara Hepworth