He now devoted his great oratorical and other talents to forwarding the cause of Catholic emancipation, and his influence was specially marked in his own county of Waterford, while his standing among his associates was shown by his being chosen to write the address to the people of England.

But he was specially anxious to secure some improvement in the education of the Irish people, and some of his proposals were accepted by Edward Stanley, later 14th Earl of Derby, and the government, he was chairman of a committee which inquired into the condition of education in Ireland, and it was partly owing to his efforts that provincial colleges were established at Cork, Galway and Belfast.

His work as an educational pioneer also bore fruit in England, where the principles of state control and inspection, for which he had fought, were adopted, and where a training college for teachers at Battersea was established on lines suggested by him.

From 1835 to 1847 he was MP for the Waterford City constituency, from 1839 to 1841 he was a Lord of the Treasury, from 1846 to 1849 he was Secretary to the Board of Control, and in 1849 he was sent as British minister to Greece.

Laetitia threw herself in a suicide attempt into the Serpentine and was rescued by Captain Studholme John Hodgson (1805–1890), a British Army officer who became her lover.