Harry Warner Farnall was born at Burley Park, Hampshire, England, on 18 December 1838, the son of Mary Warner and her husband, George Rooke Farnall, a wealthy landowner and justice of the peace. Details of his early life and education are obscure, but he had substantial capital when he emigrated to Auckland, New Zealand, around 1860.
Farnall took up land at the Wade (now Silverdale), north of Auckland, and soon became involved in politics. He represented Northern Division on the Auckland Provincial Council in 1868–69 and 1871–72, was a member of the Whangaparaoa Highway Board, and was elected to the House of Representatives for Northern Division in March 1869 and for Rodney in February 1871. An advocate of Henry George's single-tax theory, Farnall concentrated on land and taxation issues, and sought, without great success, to increase public works expenditure on the underdeveloped North Auckland region. He was said to be a poor speaker, however, and made little impact as an MHR.
On 28 May 1870 Farnall married Emma Rose Wilkinson at Hurstpierpoint, Sussex, England. He resigned from political office in January 1872, and with his wife, returned to England for personal reasons. Before departing he accepted an offer from the Fox–Vogel government of the post of emigration agent. Farnall arrived in London in July, but New Zealand's agent general there, Isaac Featherston, who believed that the appointment of emigration agents was his responsibility, refused to recognise him. Farnall was then dispatched to Belfast, where, despite Featherston's indifference, he established a successful emigration office. In December 1872 he first met George Vesey Stewart, who proposed a scheme to bring Ulster settlers to New Zealand. Featherston reacted coolly to Stewart's plan, but Farnall took it up enthusiastically. He spent much of the following 2½ years promoting the venture in northern Ireland and negotiating with the Auckland and New Zealand governments on Stewart's behalf. Indeed, Stewart would later give Farnall much of the credit for the success of the Katikati Special Settlement.
Meanwhile, Farnall's relationship with Featherston deteriorated to 'open hostility', and on 28 June 1873 he was summarily dismissed. He continued to work with Stewart in Belfast at his own expense, and in December 1873 he was offered a post as emigration agent for the Auckland provincial government. He accepted, but the appointment was never officially confirmed and Farnall worked for a further 18 months without salary, believing that he would be paid on his return to New Zealand. Amid the difficult circumstances of his work he suffered personal tragedy when, on 3 May 1874, at Bath, Emma Farnall died in childbirth. There were already two children.
Farnall left Belfast on 8 June 1875 on the Carisbrooke Castle with the first party of 400 emigrants bound for Stewart's settlement at Katikati, arriving at Auckland in September. He confidently expected compensation for his unpaid work and reimbursement for expenditure of £1,300 of his own money. However, neither the Auckland Provincial Council nor the general government would accept responsibility. Within four years Farnall was declared bankrupt, with debts amounting to nearly £3,000. For the rest of his life he lived in comparative poverty.
On 25 May 1876, at Mangawai, Farnall married Isabel Mary Grange. They were to have at least five sons and a daughter. Farnall was a committed follower of the Anglo-Israel faith, which held that the Anglo-Saxon people were a lost tribe of the Israelites. He established an Anglo-Israel association in Auckland in October 1881, lectured regularly and published an essay on the movement. His vision of the noble destiny of the Anglo-Saxon race gave rise to a concern for social reform. He soon returned to politics, but, in line with his beliefs and his own downward social mobility, henceforth devoted his energy to the advancement of working-class interests. He was to become one of the leading figures in Auckland's fledgeling labour movement.
In May 1883 Farnall helped revive the Auckland Trades and Labour Council and in June 1884 became its secretary. He unsuccessfully contested parliamentary seats as a labour candidate in 1881 and 1884, attended the first New Zealand Trades and Labour Congress in Dunedin in 1885 and was secretary of the second held in Auckland in January 1886. In 1889 he became president of the New Zealand Radical Reform League, and in June that year he founded the first New Zealand branch of the American labour organisation, the Knights of Labor, and was its first secretary. Farnall also helped to organise Auckland tailoresses in 1890 and became secretary of their union. In addition to these activities he edited one of New Zealand's earliest labour journals, the Watchman, from 1884 to 1886, and wrote The industrial depression in New Zealand (1890), a polemic against land monopoly and class privilege.
Farnall balked at being labelled a 'labour agitator', describing himself as a 'guide, friend and counsellor' to the labour movement. He explained that he had no special affection for labour, but saw the workers' struggle as part of a larger struggle for general social reform. His moderate views sat comfortably with the Auckland Trades and Labour Council's programme of the mid 1880s, which sought higher wages and improved work conditions, universal male suffrage and more public works, and generally discouraged strikes. Under Farnall's leadership the Auckland TLC was the only trades and labour council in New Zealand to survive the 1880s depression.
The labour movement, however, was changing dramatically in 1889–90. There was a remarkable upsurge in the number and membership of trade unions, and a more class-conscious unionism emerged, led by John A. Millar and the Maritime Council. Farnall was increasingly seen as a conservative and his involvement with the Knights of Labor, essentially a middle-class radical organisation, strained his relations with other labour leaders. Farnall sought to stem the rising tide of militancy within the Auckland TLC, but was overtaken by events. On 17 July 1890 he was forced to resign as secretary of the council, and on 16 September he was ousted from the tailoresses' union amid accusations that he had procured scab labour for employers during the maritime strike. Farnall had certainly been a vocal critic of Millar and the strike, but he strongly denied the allegations.
He remained recording secretary of the local assembly of the Knights of Labor, which he considered a 'nobler organisation' than the 'selfish' trade unions. He also contested the 1890 general election, but, deserted by labour voters and in failing health, he was soundly defeated. After collapsing at an election meeting, Farnall spent some weeks at the Rotorua and Te Aroha spas. He made a partial recovery, but while returning to Auckland he died at Okoroire, near Matamata, on 5 June 1891, leaving his wife with six children aged between three and 14. Farnall was buried at Devonport in Auckland, the funeral party crossing the harbour by steamer.
Tall, angular and heavily bearded, Farnall was a restless and energetic figure. His commitment to social justice was undoubted, but his critics considered him tactless and inflexible, and he was said to be a poor administrator. His public career was marred by controversy and misfortune; he also experienced financial ruin and personal loss. Yet he faced these setbacks with stoicism and some courage, and his contribution to the development of organised labour in New Zealand was considerable.