O'Shanassy, John (1818–83), Australian politician and premier of Victoria, was born at Ballinahow, near Thurles, Co. Tipperary, in 1818, one of four children of John O'Shanassy, surveyor, and Margaret Dwyer, the daughter of a farmer. With the abrupt curtailment of his education as a result of his father's death in 1831, he was apprenticed to a Tipperary draper and wine and spirits merchant. In 1839 he married Margaret McDonnell, of Thurles, and in July of that year the couple sailed for Sydney, where relatives had already settled. On their arrival at Hobson's Bay on 15 November, a chance meeting with an Irish priest convinced them to settle near Melbourne. O'Shanassy bought a farm, but did poorly because of a lack of capital, drought, and low prices. In 1845 he moved to Melbourne and opened a small drapery shop.
Financially secure from his successful drapery business, in 1846 O'Shanassy entered politics, winning a by-election to become a member of the Melbourne council. With the separation of Victoria from New South Wales in 1851, he was returned as a member for Melbourne in the first legislative council elections that September, and for the next five years was the virtual leader of the opposition (1851–55). With the gold boom in Victoria, beginning in 1851, he took up the cause of miners’ rights and in 1852 urged the government to sell land near the goldfields for agricultural purposes. He was also a member of the 1853–4 select committee inquiring into a constitution for the new colony, where he firmly supported a bicameral legislature. After the advent of responsible government in 1855, in the ensuing election for the legislative assembly O'Shanassy was elected for two constituencies, Melbourne and Kilmore, but chose to represent the latter (1856–65).
In March 1857 O'Shanassy formed the first of his three administrations, though the fragile governing alliance soon broke and he resigned after only seven weeks. A year later he formed his second administration (10 March to 27 October 1858), which eventually fell on the defeat of an electoral bill. O'Shanassy then remained in opposition until the fall of the incumbent ministry in November 1861. At that point he formed his most successful administration, with Charles Gavan Duffy (qv), who had been a member of his two previous governments, as minister for lands. His government passed legislation on local government, crown lands, the civil service, and electoral reform. O'Shanassy resigned on 27 June 1863 over a revenue question in the assembly and spent the next three years in opposition. He declined to run in the 1866 elections because of ill health and restricted political movement in the assembly.
In 1866 O'Shanassy took a year abroad and returned to Tipperary as a successful emigrant. He also visited England, and in Rome was appointed a knight of the Order of St Gregory by Pius IX for his services to catholic education. During the 1850s, as the leading Irish catholic in Melbourne, he pressed catholic school claims on the denominational schools board. Earlier he co-founded the St Patrick's Society and served as its president (1845–51); the society boosted his position in the catholic community. In the later 1860s Duffy displaced him as the leader of the catholic interest in parliament. As a member of the legislative assembly for Belfast (later known as Port Fairy) (1877–83) his main aim was to retain state aid for non-government schools which was to cease in 1878. In 1879 he became a prominent activist in the newly formed Catholic Education Defence Association. He campaigned on the education issue in the 1880 election against the incumbent government and, though he was not close to forming a ministry, wielded influence by holding the balance of power.
O'Shanassy's influence waned as he became more and more conservative; even his catholic Irish support declined when he came out against the land war. He refused to have any association with John Redmond (qv) when the latter visited Australia in the spring of 1883. In March 1883 he lost his last election to a young Australian catholic. He died 5 May 1883. Predeceased by his eldest son, he had two other sons and three daughters. He was made CMG in 1870 and KCMG in 1874.