Walsh, Michael (‘Mike’) (1810–59), politician and newspaperman, was born 4 May 1810 in Youghal, Co. Cork, son of Michael Welsh, a protestant cabinetmaker, reputed in some sources to have been a United Irishman involved in the 1798 rising, and Eileen Welsh (née Keefe). He was brought to America as a young child by his father, who settled in New York city and opened a furniture store and mahogany yard; the mother followed some time later. Receiving little formal education, he was apprenticed at age 16 to a lithographer. Probably leaving before the expiry of his term, he wandered for some years through the southern states to New Orleans (1830s), working at a range of jobs, including cabin boy, deckhand, and fireman on Mississippi riverboats. By 1839 he had returned to New York, where he was working as a newspaper reporter. In the early 1840s he emerged as the foremost spokesman of the ‘shirtless’ or ‘subterranean’ Democrats, a loose coalition of lower-class militants seeking to wrest control of New York's Democratic party from the moneyed Tammany Hall oligarchy of merchants, financiers, and attorneys. In 1840 he founded the Spartan Association, which, combining the character of a secret fraternal society, workingman's club, and urban street gang, was among the first and most effective of the organised gangs that characterised the city's politics of that era. Employing strong-arm tactics to challenge the ‘wirepullers’ who manipulated candidate selection, the Spartans forcibly removed political opponents from ward meetings and nominating conventions, and ejected rival politicians from speakers’ platforms, seeking through intimidation to secure the selection of sympathetic candidates. On three occasions Walsh stood unsuccessfully for public office on candidate slates opposed to the official Democratic nominees of Tammany. Colourful and flamboyant, he was a fiery public speaker, noted for hilariously vitriolic, extemporaneous denunciations of the powerful and wealthy. Given to stagy mannerisms and theatrics – his lieutenants were nicknamed after Napoleon's marshals – he cultivated the image of the plebeian dandy, attired in dishevelled clothing, with silver-tipped cane and diamond ring.
After publishing his own short-lived newspaper, the Knickerbocker, Walsh was successively city reporter (1841) and Washington correspondent (1842) with the New York Aurora, a pro-Democratic daily edited for a time by Walt Whitman. In 1843 he was co-founder and editor of the Subterranean, a spicy, truculent weekly. Under the motto ‘independent in everything, neutral in nothing’, Walsh's journalism expressed genuine concern for the plight of common people, alongside vituperative excoriations of political corruption and cronyism, vested interests, and privileged elites; his rhetoric was remarkable for witty hyperbole, coarse invective, and malicious insinuation. Asserting that ‘no man can be a good political democrat without he's a good social democrat’ (quoted in Wilentz, 331), he elaborated a radical anti-capitalist variation of artisan democratic republicanism, urging the labouring classes to represent their own interests, rather than follow middle-class reformers or opportunists. He published a collection of Speeches, poems, and other writings (1843). Attracted briefly to the land-reforming agrarianism of George Henry Evans and his programme of free land grants to homesteaders as a method to relieve urban poverty, he merged the Subterranean with Evans's Working Man's Advocate (1844), and joined the Evans-led National Reform Association. Within a year he broke with Evans, owing to conflicting egos and styles, and revived the Subterranean as an independent publication (1845–7). He was imprisoned twice for libel; on the second occasion, amid a concerted campaign for his release, he was freed by a gubernatorial pardon after serving half of a six months’ sentence (1846).
Receiving a Tammany nomination in deference to his popularity, Walsh was elected to the New York state assembly (1846); his re-election as an independent (1847) affirmed his personal support. Within the legislature he pursued a reform agenda, calling for abolition of the corrupt contract system on public building projects, regulation of working conditions of apprentices and minors, and a shorter working day. The momentum provided by his urban power base being diluted at state level, he made little substantial impact. With New York Democratic politics increasingly dominated by internal divisions over the slavery issue, Walsh aligned with the party's pro-slavery wing. Rewarded with Tammany preferment, after serving a third term in the state assembly (1851), he was elected to the US house of representatives (1852). Deriding abolition as a hypocritical diversion from the reform question by effete do-gooders allied with labour-exploiting northern entrepreneurs, he made his mark in congress as a northern voice for southern slave-owning rights and also attracted some notice as a satiric critic of wasteful expenditure that benefited vested interests. Defeated for re-election by a mere fifteen votes (1854), he charged fraud in the count; his opponent, John Kelly, a future Tammany chief, counter-charged that neither Walsh nor his father had ever been naturalised, thus rendering him an alien ineligible for the office.
Walsh married Catherine Wiley (or Riley); they had one son and two daughters. His last years dominated by increasingly debilitating alcoholism, he lived on sporadic journalism, his reputation, and his wits. He travelled widely in Europe (1856–7), probably as an agent in Russia for naval architect George Steers, designer of the yacht America, whose career Walsh had long promoted; after pursuing a riotous and dissipated course, he returned travelling in steerage, ill and penniless. He visited Mexico (1858), presumably as emissary for American filibusters contemplating intervention there. Claims in contemporary and retrospective secondary sources that the purpose of these foreign missions was engagement in unofficial diplomacy or espionage on behalf of the US government cannot be substantiated. After a night of saloon-crawling, he was found dead in the basement area of an Eighth Avenue shop on 17 March 1859, and was interred in Green Wood cemetery, Brooklyn. Though the mainstream press scotched suspicions of foul play, speculating that he had accidentally fallen down steps, and had been robbed of his watch and chain when unconscious or deceased, a coroner's jury ruled that violence had been involved in his death.