Moore was born on 28 May 1779 at 12 Aungier Street, Dublin. An easing of the penal laws against Roman Catholics in 1793 allowed him to enter Trinity College, Dublin, with view to a legal career. A close friend was Robert Emmet, whose death inspired him to write 'O breathe not his name', but Moore stayed aloof from the United Irishmen. Another friend, Edward Hudson, awakened his interest in Irish music, and both were moved by the Irish airs of Edward Bunting.

In 1799, Moore entered the Middle Temple in London. It was his talents as a singer and pianist, however, which made him an immediate favourite of London society; when his translation of the Odes of Anacreon was published in 1800, he was able to dedicate it to the Prince Regent. In 1803, through the influence of Lady Moira, Moore became admiralty registrar in Bermuda, but soon appointed a deputy and returned to London.

In 1808, he published his first volume of Irish MelodiesLalla Rookh (1817) were published within a year.

In 1819, Moore fled to France to escape a debtor's son after his deputy in Bermuda had stolen �6,000, but was able to return in 1822. He published biographies of Sheridan in 1825, Byron in 1830, and Lord Edward Fitzgerald in 1831, and an unusual novel-cum-history, Memoirs of Captain Rock (1824). His latter years were spent in the village of Sloperton, in Wiltshire where he died on 25 February 1852.