Mac Domhnaill, Seán ‘Clárach’ (c.1690–1754), poet, was a native of the parish of Churchtown, some 10 km to the south of Ráth Luirc (Charleville), Co. Cork. Nothing is known of his immediate family, but he appears to have come from a prosperous farming background. He received a good education, being literate in Latin, Greek, and English as well as Irish, and it has been speculated that he may have obtained one of four free places reserved for catholics in a school at Ráth Luirc founded by Roger Boyle (qv), earl of Orrery. As an adult, Mac Domhnaill farmed at Kiltoohig, about two km from Ráth Luirc, but his fortunes subsequently declined and he depended on teaching for a livelihood in his later years. He married a member of the established church, named as Agnes White in one account, but it is not known if they had any children.
Topical compositions by Mac Domhnaill include a satire (‘An t-éag tagarthach taomghonaideach’) celebrating the death in 1723 of Philippe d'Orléans, regent of France, whose policy of détente with Britain he deplored; a lament (‘Ar titim im shuan uaigneach im aonarán’) for Donnchadh Mac Cárthaigh, catholic bishop of Cork and Cloyne, who died in 1726; an expression of joy (‘Tá Iarla Chlainne Cárthaigh le hábhar ag teacht ón gcoróin’) at incorrect reports in 1734 that Robert McCarthy, Lord Clancarty, was about to be restored to the estate forfeited by his father at the revolution; and a poem (‘Déanfad tráchtadh go tais’) celebrating the appointment in 1748 of Richard Walsh, a one-time schoolmate, as catholic bishop of Cork. But Mac Domhnaill's principal theme was Jacobitism, and he charted the varying fortunes of the Stuart cause in a series of works from the 1720s onwards. Having identified Philippe d'Orléans as ‘an t-aonphosta san ler obadh ar ár gCaesar teacht’ (‘the single chief by whom our Caesar's arrival was prevented’) in the 1720s, he reassured his audience during the peaceful 1730s that the Pretender would come (‘tiocfaidh bhur Séamas cé gur moilleadh a theacht’ – ‘your James will come although his arrival was delayed’). A song (‘Éistigí lem ghlórtha a mhórshliocht Mhilesius’) composed around 1742 spread the news of Spanish successes against Britain in the war of Austrian succession, while he claimed in a work (‘Gach Gael geal greannmhar tachtadh le cóbaigh’) composed during the 1745 rising in Scotland that a French landing was imminent and urged his listeners to prepare for battle. His political opinions were not changed by the failure of the '45, and a Scottish influence is evident in some subsequent works: these include a translation of the song ‘My laddie can fight’ and the Jacobite anthem ‘Mo Ghille Mear’ (‘Bímse buan ar buairt gach ló’) which was set to a Scottish air and became his best known work.
Mac Domhnaill's support for the Jacobite cause may have been more than rhetorical and on at least one occasion he left home and went into hiding. Seán Ó Tuama (qv) of Co. Limerick, Éamonn de Bhál (qv) of Co. Cork, and Liam Inglis (qv) of Co. Tipperary were all moved to write poems lamenting his flight and it seems to have been generally believed that he had gone abroad, but a composition of his own (‘Lá is mé tríd an tír ag taisteal’) which states that he was ‘ar díbirt ag dlí na Sacsan’ (‘banished by English law’) suggests that he may have travelled no further from Cork than Co. Clare. It is also possible that his brush with the law may have been caused by a work (‘Taiscidh a chlocha fé choigilti gcoimeád criadh’) in which Mac Domhnaill savagely denounced a recently deceased landlord, Col. James Dawson of Aherlow, as an oppressor of the poor and the weak, rather than by his Jacobite compositions.
Mac Domhnaill's literary eminence was acknowledged by his fellow poets, three of whom (Seán Ó Tuama, Aindrias Mac Craith (qv), and Fr Nicholas O'Donnell) composed verses in his honour when he visited the ‘court’ of poetry at Croom, Co. Limerick, around 1735. Two Co. Cork poets, Éamonn de Bhál from Dungourney and Uilliam Rua Mac Coitir (qv) from Castlelyons, are said to have travelled to Ráth Luirc to meet Mac Domhnaill, who was described as ‘a man of great erudition’ by one of his pupils, the antiquary Sylvester O'Halloran (qv). O'Halloran stated that his former teacher had been prevented from writing a projected history of Ireland by a long illness and that he had also intended to prepare an Irish translation of Homer. Although O'Halloran believed that the poet bequeathed his papers to him, they appear to have been destroyed and only one manuscript in his hand, a copy of Keating's Foras feasa ar Éirinn, is known to be extant.
Mac Domhnaill died on 7 January 1754 and was buried in Ballysallagh cemetery, Ráth Luirc, where a contemporary headstone gives his age as 63. He was elegised by Seán Ó Tuama, Éamonn de Bhál, and Séan na Ráithíneach Ó Murchadha (qv).