Aherne, Eugene (John) (d. 1806), radical and officer in the French army, was born at Lixnaw, Co. Kerry, probably in the 1760s. According to an informant of the Irish government identified only as ‘Jones’, Aherne studied in France at the Collège de Navarre before going to Scotland in 1793 to study medicine at Edinburgh, where he became involved in radical politics and ‘acted as delegate from the Irish to the Scotch societies’ (suspect list, NAI). But it is evident from documents in his file at the archives of the French foreign office that he was studying medicine in Paris until December 1793 when he was sent by the Committee of Public Safety on a secret mission to Scotland. He visited Glasgow as well as Edinburgh, was imprisoned but released for want of evidence, and returned to France via Copenhagen, where he arrived in May 1795 and spent six months before reaching Paris and submitting a report. A plan by the French foreign minister, Charles Delacroix, to send him on a similar mission to Ireland came to nothing owing to the French government's failure to pay him arrears of expenses (April–May 1796). The impression he made in Paris on Theobald Wolfe Tone (qv), who mentions him frequently, was favourable – ‘a cool man with good republican sentiments’ (Tone, ii, 150). Whether Aherne took part in any of the French military expeditions to Ireland (1796 and 1798) beyond the preparatory stages is doubtful, but he was presumably the ‘John Ahearn’ mentioned by Miles Byrne (qv) as having been appointed a captain in Napoleon Bonaparte's Irish legion (7 December 1803) and having died at Metz in 1806 on a march to Mayence. His forename is given in French archival documents as ‘Eugène’, but Tone and Byrne call him ‘John’ or ‘Jack’. The government informant states that ‘he speaks the English language very imperfectly with a strong Munster provinciality which he generally interlards with French phrases’ (suspect list, NAI).
It seems likely that Eugene Aherne the radical was a relative of two other Eugene Aherns from Co. Kerry, one the parish priest of Lixnaw, who in 1748 endowed a bursary at the Irish college in Paris, the other the parish priest of Dunquin who died in 1819. Any connection with another Paris-educated native of Co. Kerry, Maurice Aherne (1735?–1801), who followed an ecclesiastical career in France before becoming first professor of dogmatic theology at St Patrick's College, Maynooth (1795), has not been ascertained.