Jones began in 1911 the revision of A Greek-English Lexicon, the standard dictionary of ancient Greek, with the assistance of Roderick McKenzie. A preliminary edition was published under the supervision of Jones and McKenzie in 1925, but the completed revision was published by Oxford University Press in 1940 only after both men's deaths. In a preface to the revision, the Press described Jones in these terms:
Jones began his relationship with the principality of Wales when, in 1927, he became a candidate for the principalship of the University College of Wales at Aberystwyth. His tenure in Wales would prove to be an enthusiastic one: during his time there, he learned the Welsh language and served on the committees of a number of Welsh institutions, including the council of St David's College, Lampeter, as well as Trinity College, Carmarthen, and the National Library of Wales. He also served as vice-chancellor of the federal University of Wales in 1929 and 1930. He was also elected (in 1928) to a Welsh Supernumerary Fellowship of Jesus College, Oxford in his capacity as Principal of the University College of Wales, Aberystwyth.