Cronin, Philip Henry (1846–89), Fenian and physician, was born 7 August 1846 in Buttevant, Mallow, Co. Cork, eldest child of John V. Cronin, labourer and former Whiteboy. The family emigrated to New York c.1850, and lived for a short time in Baltimore, Maryland. In 1857 – parents and children having acquired US citizenship – they moved to St Catherine's, Quebec, Canada. Until 1863 he was educated at the Academy of St Catherine's, run by the Christian Brothers. He also joined a local militia company and began giving concerts as an amateur singer. Returning to the United States c.1865, he worked as a schoolteacher and store-keeper in Pennsylvania before moving to St Louis in 1867, where he established his own drug store and became a captain in a local militia unit. He studied medicine at the Missouri College and after graduating in 1878 practised as a doctor. Charm, career-drive, political ambition, and social fluency within a wide circle of often influential friends characterised his life in St Louis, and later in Chicago, although he never married. He was selected to represent Missouri as state commissioner at the international exhibition in Paris that year, and also holidayed in Ireland, in Dublin and Mallow. Appointed (1879) professor of materia medica and pharmacy at the St Louis College of Physicians and Surgeons, and lecturer in physiology at Lindenwood University, St Louis, Cronin led a busy professional life in the city until 1881. He helped to form the St Louis free dispensary (1879) and also to draft the state medical practice act (c.1880).
Cronin moved to Chicago on accepting the post of staff physician at Cook county hospital. His private practice, at his residence on Clark St., Chicago, prospered. He engaged in municipal politics and by mid 1881 had been elected president of the 18th ward league. He was also a member of numerous nationalist and fraternal societies, and was director, shareholder, and editor of the weekly newspaper, the Celto-American, which promoted Irish-American causes. In June 1881 Cronin supported an uninhibited attack by John Devoy (qv) on the policies and character of Alexander Sullivan, president of Clan na Gael. During and after the disputes stemming from the Chicago convention of November 1881, in which Sullivan (as part of the so-called ‘triangle’ group) took decisive control of the Clan, Cronin proved an unsparing and very public critic of his leadership. After denouncing the ‘triangle’ in late 1884 for venality and dictatorial irresponsibility, Cronin was expelled (1885) from the organisation, having been found guilty of ‘treason’.
He was directly appointed to the executive of the seceding counter-organisation of Clan na Gael under Luke Dillon (qv) and John Devoy. Meetings (1886–8) between the rival committees to repair the breach frequently came to grief on the insistence of Cronin and others that reunion be accompanied by impeachment of the ‘triangle’ on charges of embezzlement. In 1888 Cronin threatened to make public Sullivan's Clan connections in order to destroy his standing in American politics as a leading member of the Republican Party. After the spy Henri Le Caron (Thomas Miller Beach (qv)) appeared before The Times commission in February 1889 and claimed that there were four other spies in the Chicago organisation, adherents of Sullivan alleged that Cronin was one of these spies. On the night of 4 May 1889 Cronin was murdered in Chicago by the ‘triangle’ supporters, Daniel Coughlan, Martin Burke, and Patrick O'Sullivan. The ensuing trial revealed his killers to be members of the Chicago police force and caused a huge outcry in the US: meetings and newspapers condemned the corruption of Chicago local government and sharply questioned the loyalty of Irish-American nationalist organisations to the American republic. Mass defections from these organisations followed. Sullivan was tried and acquitted of any involvement in the murder, but his reputation and political career were destroyed. Cronin's murder exacerbated the Clan split. The organisation did not reunite until the Philadelphia convention of July 1900, at which a resolution was passed to restore Cronin's good name.