O'Conor, Owen (O'Conor Don) (1763–1831), politician, was born 6 March 1763, the eldest of six sons of Denis O'Conor (qv) (1732–1804) of Belanagare, Co. Roscommon, and his wife, Catherine, daughter of Martin Browne of Cloonfad, Co. Roscommon. He attended an academy in Dublin, and then returned to Belanagare to work on his father's estate. At the age of eighteen he joined the Volunteers and, as a cornet, attended in 1782 the Volunteer review at Loughrea, Co. Galway. Active in local catholic politics, he was one of the delegates from Co. Roscommon at the Catholic Convention (1792–3) and was in correspondence over the years with John Keogh (qv). Later he moved to a larger stage, joining the Catholic Committee (1810) and on three occasions going on delegations to London (1811, 1813, 1816). He was to have gone to Rome with Sir Thomas Esmonde and the Franciscan priest Richard Hayes (d. 1824) to ask the pope not to countenance state participation in the appointment of Irish bishops (1815). In the event Hayes went alone and was eventually expelled. O'Conor's loyalty to Daniel O'Connell (qv) was unbroken. At the first general election after the passing of the Catholic Relief Act of 1829, O'Conor was returned without a contest as one of the two representatives of Co. Roscommon (9 August 1830), and at the general election held the following year was returned again (19 May 1831). He was the only member of the Catholic Convention to become a member of parliament.
By his marriage (20 June 1792) to Jane Moore, daughter of Edward Moore (d. 1787), a porter brewer of Mount Brown, Dublin, he became connected to two eminent catholic merchant families, for Moore's eldest daughter, Mary, had in 1775 married Valentine O'Connor (qv), while his second daughter, Joan (or Judith), was the wife of Patrick Grehan, who inherited Moore's business and was later a trustee of the lay college at Maynooth. Owen O'Conor was named as a beneficiary in the will of a distant relative, Dominick O'Conor (1723?–1795) of Clonalis, Co. Roscommon, who held the hereditary title ‘O'Conor Don’; both were descendants of Sir Hugh O'Conor, O'Conor Don (d. 1632), of Ballintober. It was disputed between Dominick's widow and his younger brother Alexander, who succeeded as O'Conor Don. Eventually, in February 1805, much of Dominick O'Conor's estate (including Clonalis) was purchased by Owen O'Conor. When Alexander O'Conor died unmarried in 1820, the title ‘O'Conor Don’ passed to Owen O'Conor.
Entering parliament far from home and nearing seventy had an ill effect on O'Conor's health. He died 12 June 1831 at Belanagare. With his wife, Jane (d. 1804), he had two sons and several daughters. The elder son, Denis O'Conor (qv), succeeded him as MP for Co. Roscommon.