Remaining in the army during the interwar period, Barker, promoted to captain on 19 August 1920, returned to England and served as a GSO3 at the War Office and later at Southern Command. In 1923 he married Violet Eleanor and together they had one son, George Worsley Barker. He then served on regimental duties for a few years before attending the Staff College, Camberley from 1927 to 1928. After graduating he returned briefly to the KRRC before returning to the War Office as a GSO3 from 4 December 1929 onwards.