Towards the end of 1847 he gave up his ministry at Tredegar owing to ill-health and, about the same time was compelled to refuse the secretaryship of the National Temperance Association for the same reason. In March 1848 he went to Cardiff to edit The Principality but had to resign in Sept. because he and the publisher had a difference of opinion on the question of accepting Government grants for schools. The following month he was appointed to the staff of The Standard of Freedom (publisher John Cassel), London. There he was an editorial assistant on The Pathway, a young people's magazine, and edited Almanac y Cymru, 1849. In Dec. 1848 he m. Rachel, fifth daughter of the Rev. Walter Lewis of Tredwstan. In Aug. 1849 he had to give up his post and return to Cardiff because of ill-health. There he undertook the editorship of Y Gymraes, under the patronage of lady Llanover (q.v.), and the Adolygydd, a quarterly. Both efforts were financial failures, and within two years were taken over by D. Rees (1801-1869) (q.v.) of Llanelly who was prepared to let Ieuan Gwynedd continue as joint editor with him. Ieuan, however, d. 23 Feb. 1852, and was buried at Groes-wen.

He wrote verse, and on several occasions competed at the eisteddfodau, but by now his poetry is little esteemed. He joined the temperance movement in 1836, and thereafter continued to write articles and letters to various newspapers and periodicals, Welsh and English, in support of that movement. The outstanding work of his life was his defence of Welsh nonconformity against the attacks of certain clergymen, and, more particularly, against the attacks of the Education Commissioners of 1847. His articles on this vexed question are to be found in the Shrewsbury Chronicle, Yr Amserau, The Nonconformist, John Bull, and the Monmouthshire Merlin; some of them were republished in pamphlet form (see below). His arguments, always strongly presented, were based on a careful preliminary study of the facts; see Facts, Figures, and Statements in Illustration of the Dissent and Morality of Wales: an Appeal to the English People by Evan Jones (London, 1849), and also A Vindication of the Educational and Moral Condition of Wales in reply to William Williams, Esq., Late M.P. for Coventry by Evan Jones of Tredegar (Llandovery, 1848).