Initially trained by his father, Theed studied at the Royal Academy Schools from 1820 and subsequently in Rome, where he remained for almost twenty years before returning to England. He was a patronised extensively by the Royal Family, and exhibited over 80 subjects at the Royal Academy between 1824 and 1885, largely portraits and genre subjects. A number of these were reproduced in parian porcelain by the Stoke-on-Trent firms of Copeland and of Brown-Westhead, Moore & Co.