O'Donnell, Thomas (Tom) (1871–1943), teacher, lawyer, and politician, was born 30 November 1871 at Liscarney, near Dingle, Co. Kerry, second eldest child among four sons and five daughters of Michael O'Donnell and Ellen O'Donnell (née Rohan). Michael joined the Land League in 1879, and in an attempt to have his rent reduced withheld payment, was evicted, and moved into a mud cabin on the edge of his farm. Seven years later, after the intervention of the land court, the O'Donnells were readmitted at a reduced rent. In the meantime Tom O'Donnell attended Farranakilla national school: in 1885 he became a monitor, and in 1890 won the Reid prize, qualifying him for a two-year course at Marlborough St. training college, Dublin. In 1892 he began teaching in Killorglin national school. Five years later he married Nora Ryan, daughter of a local publican. From 1893 he was associated with the Gaelic League: he was a founder member (1900) of the Killorglin branch, was active in the League's campaign to have bilingual instruction in national schools in Irish-speaking districts, and taught Irish to his own pupils outside school hours.
O'Donnell welcomed the establishment (1898) of the United Irish League by William O'Brien (qv). Its main object was to break up the large grass farms by compelling graziers to sell their lands to the congested districts board for redistribution among small tenants. O'Donnell was indefatigable in spreading its message. In the general election of 1900 he stood successfully as UIL candidate for Kerry West. His attempt to deliver his maiden speech in the house of commons in Irish received considerable publicity, and he became one of the most active members of the Irish party. He accompanied his leader on a delegation to the USA (1901), became the party's spokesman on Irish education (1902), and exerted pressure on landlords in his constituency to sell to tenants under the land act of 1903; and in 1908 he and his fellow MP John P. Boland (qv) forced their reluctant party to insist on Irish being a compulsory subject for matriculation in the National University of Ireland. Like other members of the party, O'Donnell was caught up in the final drive towards home rule and addressed meetings in his constituency and throughout Great Britain. After the home rule bill received the royal assent, he called for unity behind the leadership of John Redmond (qv). In the meantime he had not neglected the other interests of his constituents: he secured a grant for the Tralee and Dingle light railway and placed it on a sound financial footing; with Bishop John Mangan of Kerry, he acted as a mediator in negotiations between landlords and tenants; he successfully applied to Andrew Carnegie for a grant for a library and second-level school in Killorglin (which became the successful Killorglin Intermediate School), championed the cause of the fishermen in his constituency, and supported Irish industry. After a visit to Denmark he continually spoke and wrote on the need to improve farming methods along lines followed in that country.
O'Donnell and his fellow MPs opposed the Irish Volunteers. On the outbreak of war in 1914 he was second only to his leader in urging recruitment to the British forces, and his clashes with Sinn Féin supporters on this issue were bitter. In the aftermath of the 1916 rising his attempts to concern himself with the wellbeing of Kerry Sinn Féin prisoners were rejected. Despite the Irish party's anti-conscription campaign, the flow of support to Sinn Féin continued unabated. O'Donnell, bowing to the inevitable, did not contest the general election in December 1918. In Kerry the Irish party ceased to be a viable organisation.
O'Donnell had qualified as a barrister in 1905. This now assumed a new importance as he had to provide for a wife and seven surviving children. When the IRA began to exert control over the Killorglin district, O'Donnell moved with his family to Dublin (1921). A much embittered man, he subsequently availed himself of every opportunity to criticise vigorously the native governments established after the Anglo–Irish treaty. From the beginning of 1926 O'Donnell consulted former political acquaintances on whether they would be willing to set up branches of a new political movement that he proposed to establish. In June a Dublin central organising committee was formed to launch the new party with O'Donnell and Captain William A. Redmond (qv) as co-chairmen. The party, named the Irish National League, won eight seats in the general election of June 1927. O'Donnell stood unsuccessfully in Clare. An attempt (16 August 1927) to replace the government by a coalition of the Labour party and the National League, supported by Fianna Fáil, failed by one vote. O'Donnell, who had been a major player in the attempt, was particularly disappointed, as Redmond had told him he would be proposed for attorney-general in a coalition government. National League supporters were not impressed by the political somersaults of their leaders, and the party was reduced to two seats in the general election of September 1927; its decline continued and early in January 1931, at a meeting attended by O'Donnell, it was dissolved. In the meantime O'Donnell had been a prominent critic of the retention of the land annuities. This led him to join Fianna Fáil and to stand as a candidate in Dublin county in the 1932 general election. After Fianna Fáil formed a government, he appeared as state counsel in an increasing number of cases. He was called to the inner bar (April 1932), served as a temporary judge in the Cork circuit court (1935–8), and was chairman of the military pensions board (1938–43) and judge of the Clare, Kerry, and Limerick circuit court (1941–3). He died 11 June 1943. His pamphlets included Connacht and Kerry under the congested districts board (1903), A trip to Denmark (1908), Free State finance : address delivered at the National Club, Dublin, on 9 January 1925 (1928), and The partition of Ireland (1929). A portrait by Seán O'Sullivan (qv) is (2005) in the possession of his grandson, Mr Justice Dermot Kinlen; his papers are in the NLI.
Of his ten children two died in infancy and a daughter, Nora, died aged 14 (1916). Subsequently his sons Michael and John practised as GPs; the third, Horace, emigrated to the USA. Another daughter died young in 1928, and later Eileen, Maura, and Mona married Louis Kinlen, John Rolph, and Cyril Boden respectively.