He entered William Shipley's drawing school in the Strand, London, then directed by Henry Pars, in Nov. 1761, and in March 1763 he became Richard Wilson's pupil, agreeing to pay Wilson fifty guineas for two years’ tuition. He was awarded premiums by the Society of Arts for figure drawing in 1764 and for landscape painting in 1767 and 1768, and was elected a member of the Incorporated Society of Artists in 1766.

For the following ten years Thomas Jones devoted himself to landscape painting in Wales and in London and other parts of England. His friends included Garrick, Evan Lloyd (1734-1776) (q.v.), Farington, and Francis Wheatley. He left for Italy in 1766 and settled in Rome, moving to Naples in 1780. His circle of friends in Italy included Towne, John Smith, Edward Pars, and Day, and he carried out a large number of commissions there.

He returned to England in 1783 with his wife, Maria, and two daughters, and continued to paint, avowedly at times imitating Wilson and Zuccarelli. On the death of his elder brother in 1787 he succeeded to the estate at Pencerrig and finally left London in 1769. He was elected high sheriff of Radnorshire in 1791 and a magistrate for the county in the following year.

Thomas Jones exhibited ten pictures at the Royal Academy between 1764 and 1798 and a large number at the Society of Artists’ exhibitions. Some of his work was engraved and examples of his paintings are to be found in public and private collections. Many are still owned by the family. He d. at Pencerrig in May 1803.