Dunne was born at Ballymanus, the son of a prosperous tenant farmer on the estate purchased for Henry Grattan by the Irish Parliament in gratitude for his services.
Dunne was described as ‘a plain, shrewd, clear-headed man’ and a ‘warm friend of free trade’. A Liberal, he favoured the ballot and an extension of the franchise, the repeal of the Ecclesiastical Titles Act and ‘a final and satisfactory settlement’ of the Irish land question.
Dunne was the only tenant farmer to be returned at the election, although given his social background he was ‘hardly … a typical one’. He was, however, the first tenant-right candidate to be returned for an Irish county, and attended the conference of the Tenant League in September 1852, seconding one of its resolutions.
By January 1854, however, Dunne’s allegiance to the Irish party appeared doubtful. Yet, despite a ‘natural tendency … to co-operate cordially with Lord Aberdeen’s Government’ (Dunne habitually sat on the government benches), he opposed Gladstone’s budget over the issue of income tax, 2 May 1853, and was not among the ‘so-called “Liberal” Irish members’, castigated by the Freeman’s Journal for proclaiming ‘Lord John Russell as their parliamentary leader, their guide, and prophet’.
Dunne was, however, generally regarded in his constituency as ‘an active and steady friend of the popular cause’. He had been one of the ‘warmest and most ardent supporters’ of the Queen’s County Independent Club from its foundation, and drew widespread support from the Catholic clergy and county freeholders. He sat on the committee of creditors established to negotiate a compromise settlement after the collapse of John Sadleir’s Tipperary Joint-Stock Bank in 1856, but does not appear to have sat on any parliamentary select committees or introduced any bills. He continued to lend support to the Tenant League and the faction of the Irish party led by George Henry Moore and Frederick Lucas, voting for Shee’s ill-fated tenants’ improvements compensation bill, 4 May 1855.
Dunne, being one of two remaining ‘Sadleirites’ in parliament, was reported to have displeased the Catholic clergy of his native county. However, he held his seat at the ensuing general election, being described as a ‘moderate Young Irelander’, and came second in the poll after a violent contest involving another challenge from Fitzgerald.
At the 1859 general election he proclaimed his adherence to the cause of independent opposition, claiming never to have ‘asked for or received any government private favour’, and endorsed land reform, the ballot, the repeal of the Ecclesiastical Titles Act and denominational education. He was duly endorsed by the Catholic clergy of his native county and returned unopposed.
A ‘country gentleman’, Dunne was regarded as a ‘kind and indulgent’ landlord, a ‘just’ magistrate and was ‘ever the kindly host, the cheerful companion’. A renowned ‘turfman’, he owned a number of famous thoroughbreds and took a prominent part in ‘all the racing events of the province’, reviving Heath Races in 1844, and becoming ‘one of the oldest patrons of Irish racing … a sportsman from birth, and popular with all classes’.
Dunne was said to ‘possess many of the more important qualifications necessary to constitute a popular representative’ but, despite enjoying ‘the entire confidence’ of the popular vote in Queen’s County, and being ‘urged in the strongest manner to allow himself to be put in nomination’, he retired at the 1865 general election, citing ill health.