William Fitzherbert was born on 15 August 1810 at Winterborne, Houghton, Dorset, England. He was the third son of Samuel Fitzherbert, an Anglican clergyman, and his wife, Ann Joyce. Fitzherbert was educated at the local dame school, Sherborne Grammar School, and the Merchant Taylors' School. From 1828 to 1832 he was a student at Queen's College, Cambridge. He graduated MA, second junior optime and first in the second class in Classics. He then undertook medical training at the École de Médecine, Paris, and Charing Cross Hospital, London. According to his brother Herbert this decision to take up medicine was 'abrupt and headstrong', following disappointment at not getting a college fellowship. In later life Fitzherbert declared that he had taken a wrong turn in going in for medicine and regretted not taking up the study of law instead. He never practised medicine in New Zealand.
Throughout the 1830s Fitzherbert was in a state of extreme uncertainty about the course of his career. He described himself while studying as 'entirely dependent on my mother, who is a widow with five other children all of them more or less dependent on her.' In 1838 he conceived a plan to emigrate as a settler, not as a doctor, to the United States, but Herbert, who had charge of the family's finances, vetoed the idea, considering 'a settler in America as only one degree above an inmate of an English workhouse'.
In 1839 Fitzherbert graduated MD and commenced practice in London. However, in the same year, with Herbert's approval, he decided to emigrate to New Zealand. Still hoping to gain a fellowship at Queen's College, he modified his plan and became a partner with T. M. Partridge. They bought a land order from the New Zealand Company and a consignment of goods with an investment of £1,000 of the Fitzherbert family's money. Partridge went out to New Zealand on the Adelaide, the first consignment was sent on the Glenbervie, and Fitzherbert remained behind as the English-resident partner. In January 1840 he had been finally admitted to a bye fellowship at Queen's College, and in late 1840 or early 1841 he married Sarah Jane Leigh in London.
Consumed with anxiety as to what was happening in Wellington and frustrated in an attempt to be elected physician to a leading London dispensary, Fitzherbert decided to join Partridge, and in April 1841 sailed with a load of goods on the 109 ton Lady Leigh, which he had purchased. His plan was to return to England after selling the goods and winding up the business. But he found on arrival in Wellington on 15 September 1841 that the economy of the infant settlement was depressed and the merchandise could not be sold. He decided to remain in Wellington and sent for his wife. He then set up in business as a merchant of whale oil and bone, while living on a small farm on the slopes of Mt Victoria.
Fitzherbert came close to abandoning Wellington. After the earthquake of 1848 he chartered a vessel, the Subraon, and embarked for Sydney with a number of other 'refugees' and a cargo of whale bone and oil. However, the Subraon was wrecked at the harbour entrance and he had to return to Wellington. Critics later taunted him with having run away from the earthquakes.
Fitzherbert's fortunes improved after an unpromising start. He lost most of his original capital but eventually moved out of the declining whale oil and bone business and invested in pastoralism in Wairarapa. As a prominent member of the Wellington Settlers' Constitutional Association he became increasingly involved in local affairs. By the early 1850s he had prospered to such an extent that he was able to devote all his energy to politics. He represented Wellington City (1853–57 and 1865–69) and Hutt (1859–65) on the Wellington Provincial Council. He was one of the leading members of the 'Featherston party' and was closely associated with Isaac Featherston in the management of the council. He also became involved in central politics, representing Wellington City (1855–58) and Hutt (1858–79) in the House of Representatives.
During his years as a politician Fitzherbert continued to acquire land in the Wellington region. It has been suggested that he manipulated provincial land policies to his own advantage. After initially securing 2,060 acres of New Zealand Company compensation land at Rangītikei, he purchased 1,251 acres of Crown land at Lowry Bay and Wainuiomata in 1864 and 1865. By 1882 he held 709 acres of land in Hutt county, and town land worth £5,832 in Lower Hutt. He lived in Wellington city for a number of years, and then in 1850 shifted out to the Hutt Valley with his wife, daughter and two sons.
In 1864 Fitzherbert was appointed colonial treasurer in the Weld ministry. The financial situation at this time was serious owing to the strain of financing the New Zealand wars, and he earned high praise for the steps which he took to alleviate it. While 'self-reliance' – withdrawal of British troops – was negotiated, he obtained from the British government remission of a £750,000 debt incurred during the wars.
When Edward Stafford replaced Frederick Weld as premier in 1865, Fitzherbert was reappointed colonial treasurer. He decided that it was necessary to revise the system for distributing revenue between the provinces and the central government. In his 1867 financial statement he announced the consolidation of all provincial loans, which were in future to be the responsibility of central government. He called this policy 'putting in motion the vast power of a common credit, which is now frittered away and wasted by being exercised provincially.'
In the late 1860s Fitzherbert became discontented with himself and with the country: he thought that governments had fallen into 'a dreamy and dormant state' and had 'overlooked too much the great work of colonization, which we ought to have considered as those who had to found a new country.' In 1868 he wrote from England to his colleagues, proposing a policy to promote immigration and public works. Nevertheless, he became a fervent critic of the policy when Julius Vogel introduced it, reverting to strong provincialism after succeeding Featherston as superintendent of Wellington province in 1871. He proved to be a constructive critic when he promoted the establishment of the Public Works Department to ensure the efficient administration of Vogel's programmes. As superintendent he did much to restore the province's prosperity. He placed a considerably greater emphasis than had Featherston on closer settlement, especially in Manawatū.
Fitzherbert became speaker of the House of Representatives in 1876 and was knighted the following year. In 1879 he was appointed to the Legislative Council and made speaker, a position which he held until his death. After entering the Legislative Council he attended the Imperial Conference in London in 1887 and the postal conference in Sydney in 1888 as a government representative. He continued to work up until the end of his life: he died on 6 February 1891 at the age of 80. Sarah Jane Fitzherbert had died on 1 August 1886.
C. R. Carter described Fitzherbert in middle age as 'a wiry and compactly-made little man, with a thin sharp visage – a large Roman nose – grey whiskers and a large head, nearly bald. Intellectuality, blended with a certain kind of comicality, was stamped on his features'. As a politician he could be bold and innovative, going to the heart of complex issues and offering imaginative solutions, as with the financial crisis of the mid and late 1860s. But he also acquired a reputation for using unscrupulous methods to attain his ends. Especially notorious was his ingenuity in justifying the receipt of official pensions while continuing to hold lucrative positions.
Fitzherbert was generally acknowledged to be a forcible and eloquent speaker, with a capacity for uttering memorable phrases. It was remarked that his speeches, especially in the House, were performances: 'he alternately advanced and retreated – gesticulated and leered – smiled and apostrophised – in such a way, as to rivet the attention of his hearers, while he convulsed them with laughter.' Few 'could better assume virtuous indignation, injured innocence, and hopeless consternation; or excel him in effective by-play.' At times, however, his style of speaking could be discursive: some suspected a deliberate intention to obscure meaning. He frequently indulged in elaborate metaphors and long anecdotal digressions.
Fitzherbert was an outstanding debater, one of the best in the nineteenth century House of Representatives. He was renowned for his ability to speak without notes and respond with a precise memory of everything said by opposing speakers. This he attributed to the cultivation of his memory at the dame school, where he had had to give summaries of every sermon that he heard preached. He would often sit silent in a debate, every muscle in his face rigid, apparently asleep, and then arise and recall and demolish every one of his opponents' arguments. He liked to indulge in a sarcastic form of humour. Sometimes he went too far and made 'clever and stinging speeches' that damaged relationships.
Although influential, Fitzherbert was not popular with other politicians. Henry Sewell said that he was exceedingly disliked and was 'repulsive in manner'. The mystery with which he liked to surround his opinions and intentions repelled trust. Some called it reserve, a habit of being 'too shut up within himself'. Others saw the reserve and 'distance' as a pose. He was always acting, never allowing his inner self to be seen or heard.