He was educated at Paris, at Montpellier, and afterwards at the Irish College in Toulouse, where he studied theology,[1] and became acquainted with Henry Essex Edgeworth, then a boy, living there with his father.
On his ordination to the priesthood in 1761, Moylan was appointed to a curacy at Chatou, a relatively affluent suburb of Paris, by the archbishop, Christophe de Beaumont, and for a time served as his secretary.
Moylan had no sympathy with violence as a means of redressing wrong, and therefore condemned the Whiteboys[1] When the French fleet appeared off the south coast of Ireland in 1796, Moylan issued a pastoral letter to his flock urging them to loyalty;[1] his native city, in recognition of his attitude, presented him with its freedom, an unusual mark of esteem to be bestowed on a catholic in those days.
The lord-lieutenant (Earl Camden) ordered one of his pastorals to be circulated throughout the kingdom, and Pelham, the chief secretary for Ireland, wrote to congratulate Moylan on his conduct.
The prelates, Moylan chief among them, were disposed to adopt these proposals in a modified form, but subsequently, on learning Lord Castlereagh's full intentions, repudiated them.
He was a most successful administrator of his diocese, and helped materially in the establishment of the Presentation order of nuns founded by Nano Nagle for the education of poor girls.