[1] Moreton's father left the House of Commons in 1720 on being raised to the peerage and the son was elected Member of Parliament for Cricklade at a contested by-election on 1 February 1721.
He was then elected MP for Calne at another contested by-election on 28 February 1723, possibly on the interest of Walter Hungerford to whom he was related.
When Walpole's government fell in 1742, Lord Ducie agreed to hold the office of surveyor of the petty customs in London in trust for Henry Bilson-Legge and Benjamin Keene, but in 1752 he asked to be relieved of it.
In 1755 he was appointed Constable of St. Briavels, Warden of the Forest of Dean and Lord Lieutenant of Gloucestershire holding the posts to 1758, and High Steward of Gloucester which he held until 1766.
He was unmarried and as his barony would become extinct, he was created Baron Ducie of Tortworth, on 27 April 1763 with a special remainder to the descent of his sister Elizabeth, who married Francis Reynolds.