 Elliot was elected to the Irish House of Commons in 1796 as a Member of Parliament for St Canice.At the 1798 election he was returned for both Carlow Borough and for St Canice, but chose to continue to sit for St Canice.He held that seat until the Parliament of Ireland was abolished at the end of 1800 by the Act of Union, when he did not initially have a seat in the new Parliament of the United Kingdom.