O'Connell was born near Cahirciveen, Co Kerry, on 6 August 1775. Adopted by a childless uncle, Maurice 'Hunting Cap' O'Connell of Derrynane House, overlooking Kenmare Bay, he attended English colleges in France before they were closed by revolutionaries. The O'Connells were prosperous Roman Catholics; it had been illegal to educate the boy abroad, but a 1792 Relief Act changed this and also allowed him to become a successful barrister on the Munster Circuit.

A constitutionalist in politics, O'Connell opposed the violence of the 1798 and 1803 risings, and in 1815 was distressed when he killed an opponent who had forced him into a duel. In 1823, he formed the Catholic Association; membership eventually cost a 'Catholic rent' of a penny a month. His objective was Catholic emancipation, opening up state and judicial posts and the right to sit in parliament. A powerful nationwide organisation quickly emerged, with the help of clergy, and in 1824 the government unsuccessfully prosecuted O'Connell for inciting rebellion.

In 1828, he won a by-election in Co Clare, but unwillingness to take the anti-Catholic oath of supremacy kept him out of Westminster. The following year, the government conceded Catholic emancipation; 'The Liberator', as he was now known, entered parliament after a by-election. In 1840, O'Connell again marshalled mass support in the National Repeal Association, his oratory drawing enormous crowds. However, in 1843, he accepted a government ban on a rally planned for Clontarf, on the outskirts of Dublin. and lost ground to the more militant 'Young Irelanders' under Thomas Davis. In 1844, he was found guilty of creating discontent and disaffection, and was in prison for three months before the House of Lords reversed the judgement. He died in Genoa, on his way to Rome, on 15 May 1847.

Derrynane House (l 1/2miles/ 2km SW of Caherdaniel, Co Kerry), now a national historic park and museum.
Statues in O'Connell Square, Ennis, Co Clare;
in the Crescent, Limerick; and in O'Connell Street, Dublin.
Charles Chenevix Trench, The Great Dan (1984).