Sydney Jones was born 18 June 1911, the son of John Daniel Jones and Margaret Ann (née Evans). He was educated at Cyfarthfa Castle Grammar School, then Cardiff Technical College, Cardiff University College, Birmingham University (BSc), taking 1st class honours (London) in 1932, also completing a PhD (London) in 1951. In 1938 he married Winifred Mary (née Boulton); they had two sons and one daughter.

Jones began his career at the General Electric Company, Witton, between 1933 and 1936, then taught in Birmingham [Warwickshire], until 1940. He then joined the Scientific Civil Service at the headquarters of the Royal Radar Establishment in Malvern [Worcestershire], working there for the next seventeen years, before a short spell at the Royal Aircraft Establishment at Farnborough [Hampshire]. In 1958 he moved to become Director of Applications Research at the Central Electricity Generating Board, staying until 1961, then until 1962 worked as Technical Director for R. B. Pullin Limited. Jones then moved to British Rail as Director of Research, 1962-1965, continuing as a Member of the Board of British Railways until 1976. After his retirement from British Rail he continued to serve in various positions, including as Chairman of the Conformable Wheel Company, from 1981, and Chairman of the Computer Systems and Electronics Requirement Board, Department of Industry, (1975-1978). Jones was awarded the CBE in 1971, and was made a Fellow of the Fellowship of Engineering in 1977. He died on 21 February 1990.

Jones's publications include Introductory Applied Science (1942), and papers on automatic control, railways and variable geometry elastic wheels.