During the 1830s, Ebrington led a strong body of Reformist Whigs; and he played a prominent role in establishing Whig party organisation under the new electoral system. In 1839, as Baron Fortescue, he served under Lord Melbourne as Lord Lieutenant of Ireland, until in 1841 he succeeded his father in the earldom. He went on to serve under Lord John Russell as Lord Steward from 1846 to 1850; was sworn of the Privy Council in 1839; and created a Knight of the Garter in 1856.