Hiram Hunter was born in Christchurch, New Zealand, on 10 February 1874, the son of Charles Hunter, a maltster, and his wife, Deborah Ann Eden. He was educated at the Sydenham school and followed a variety of occupations in rural areas, including farm labouring, storekeeping, road and railway construction, bush-felling, and driving. On 20 September 1898 at Christchurch Hunter married Jane Bayliss, a domestic servant. The farmer for whom Hunter was working as a teamster refused to keep a married couple, so they settled in Christchurch.
In 1902 Hiram Hunter attempted to set up a drivers' union. He was victimised by employers to such an extent that he went to work on the construction of the North Island main trunk line, then at bush-felling and storekeeping in Northern Wairoa. Around 1907 he returned to Christchurch and was involved with the Canterbury Drivers' Union. As full-time secretary from 1908 and a delegate to the Canterbury Trades and Labour Council, Hunter was instrumental in reshaping the labour movement into an assertive industrial force. Drivers were among the lowest paid at that time, receiving less than a shilling an hour for a longer day than most workers; they also required extra time at the beginning and end of each day to care for their horses. Under Hunter's leadership the Canterbury Drivers' Union organised the workforce more consistently and grew rapidly in numbers and influence. In 1909 the union enthusiastically supported the formation of a national federation of drivers as a means of securing national uniformity in awards.
Although Hunter displayed a considerable aptitude for advocacy and organisation, he made no significant contribution to the political debates in the labour movement. His undoubted ability propelled him into political roles which he ardently desired but for which he was temperamentally unsuited. He sat as a city councillor from 1911 to 1915 and 1917 to 1923. In 1914 he was president of the left-wing Social Democratic Party. His intemperate enthusiasm for the imperial cause at the outset of the First World War must have alienated many comrades, but as the government moved towards conscription Hunter restored his position in the labour movement. As secretary-treasurer of the United Federation of Labour from 1915 to 1919 he worked strenuously against compulsory service. In 1918 he received a three-month prison sentence for sedition (from which he was released after 19 days). Hunter was secretary of the Christchurch Tramway Employees' Union from 1912 to 1919, but because of his strong opposition to conscription he was banned by the employers from representing the tramway workers.
In 1911, 1914 and 1919 Hiram Hunter stood unsuccessfully for Parliament in working-class Christchurch East. During the war the Liberal incumbent, Henry Thacker, campaigned vigorously against wartime inequality and as a consequence he was able to upstage Hunter in the 1919 election.
In 1923 Hunter was elected workers' representative on the Court of Arbitration, effectively by the combined vote of the New Zealand Alliance of Labour. However, after he failed to obtain their endorsement for the next election, and made public his dissatisfaction, he fell out with the Alliance, whose president, Jim Roberts, ensured his removal in 1926. That year Hunter briefly returned to work as national organiser for the New Zealand Federation of Drivers' Unions before becoming a commercial traveller. In 1931 he stood unsuccessfully as an independent labour parliamentary candidate in Mid-Canterbury. He was expelled from the New Zealand Labour Party in 1937.
By now, having observed events in the Soviet Union, he opposed socialism, believing that it led to 'servility for the workers under the domination of dictators', and in 1938 he stood for the New Zealand National Party against his former comrade Dan Sullivan. Not even the Press took this effort seriously; Sullivan beat him by three to one and the election-night crowd booed him so loudly he could not be heard. It was an undignified end to his public career, which, according to Roberts, had been characterised by equivocation and political somersaults. Although he had failed in his attempts to enter Parliament, Hiram Hunter made some real contributions to trade unionism in its formative years and had achieved national prominence as a union leader. Hunter retired to follow his interests in dog-breeding, and died aged 92 in Ashburton on 9 May 1966, survived by two daughters. His wife had died in 1960.