William Mein Smith is said to have been born on 7 September 1799 at Cape Town, South Africa, and was baptised there on 3 October 1799. He was the eldest son of William Proctor Smith, a naval purser, later secretary to the Port Admirals at Plymouth, and his wife, Mary Mein. Mary Mein's family home was Eildon Hall, near Melrose, Scotland. William Mein Smith belonged to a military family. He went to school in Devon, entered the army as a gentleman cadet at the age of 14, and obtained his commission in the Royal Artillery in 1822, eventually rising to the rank of captain. From 1822 to 1828 he served in Canada. On 12 March 1828, at Kingston, Upper Canada (Ontario), he married Louisa Bargrave Wallace. The couple had nine children, of whom five survived infancy.
After his marriage Smith was stationed at Gibraltar, where he established a library to save soldiers from drink's 'disgrace and ruin.' He assumed the post of master of plan drawing at the Royal Military Academy at Woolwich in May 1836. In July 1839 the New Zealand Company engaged him for three years as its first surveyor general.
Late in 1839 Smith arrived in New Zealand on the Cuba, entering Port Nicholson (Wellington) on 5 January 1840. Louisa Smith and their three children arrived on 7 March 1840 on the Adelaide. Smith's first task was to lay out the company's settlement at Port Nicholson. Beginning in January, he and his three assistants laid out two towns, first at Petone and then, after April, at Thorndon. In July and August he conducted the ballot for 1,100 town sections, at Dicky Barrett's hotel. By 1841 he and his staff had surveyed a number of country sections from Pencarrow to Porirua, considerably fewer than the company's specification, in bush-clad, hilly country. To meet the shortfall, the company attempted to purchase Wanganui, where in September Smith superintended the selection of country acres, only to find that Maori considered the land had not been sold. He made a reconnaissance of Manawatu in December 1841, and supervised its survey by Charles Kettle in 1842. Smith was in Manawatu when Samuel Brees arrived to supersede him.
In September 1842 Smith was directed to map the harbours on the South Island's east coast, and he explored as far as Bluff, Stewart Island and the Chatham Islands. Unluckily, in November his cutter, Brothers, sank in Akaroa Harbour, with his sketches, charts and instruments. Afterwards he climbed the Port Hills, above Rapaki, to view the Canterbury Plains, but his report, written from memory, was of little use to the company in deciding sites for future settlement.
Smith participated quietly in Wellington public life. The first meeting of the committee formed to maintain the law of England met at his house in 1840; in 1841 he was gazetted a resident magistrate, and in 1845 became captain of the Thorndon militia. He was happiest alone with his sketchbook. His best-known work, an 1842 vista in oils of Wellington, was published as a lithograph in E. J. Wakefield's Illustrations to 'Adventure in New Zealand' (1845). It is one of about 100 of his works now housed in the Alexander Turnbull Library, Wellington. As a committee member of the Literary, Scientific and Philanthropic Institute Smith was active in establishing a library, and as a prize-winning gardener and Wellington Horticultural Society member, he introduced bamboos to Wellington. He also promoted the installation of a harbour beacon.
Early in 1845 Smith and his family moved to Huangarua, between Greytown and Martinborough, in Wairarapa, where in partnership with Samuel Revans he became a successful runholder. Smith and Revans made their first profits from their Maori lease negotiated with Te Manihera Te Rangi-taka-i-waho, by supplying meat to government troops. By 1858 Huangarua ran 20,000 sheep. By 1868 it had grown to more than 20,000 acres. Between 1854 and 1865 Smith and Revans had purchased 13,680 acres from the Crown.
Although Smith proved a clever farmer, he was reluctant to leave his profession and returned to the New Zealand Company during 1849 and 1850 as a contract surveyor. He made a sketch survey of Wairarapa and was involved with Henry Tacy Kemp in abortive purchase negotiations with Wairarapa Maori, at a time when it was proposed that the Canterbury Association settlement should be located there. In 1849 he explored Manawatu to estimate the cost of survey, and to inspect the New Zealand Company's purchase north of the Rangitikei River. Later he completed the survey with Maori assistance.
As government district surveyor in Wairarapa from 1853 to 1857, Smith surveyed Crown purchases by Donald McLean, and determined Maori reserves. He partly mapped Wairarapa, including the Wharekaka Plains, in 1854, surveyed eastward, completed a coastal survey to Castle Point and the triangulation of the Taratahi, defined the boundaries of Masterton and Greytown during his trigonometrical survey and in 1856 laid out the town of Featherston.
Smith was a member of the Legislative Council from 1851 to 1853, and represented Wairarapa from 1858 to 1865 on the Wellington Provincial Council. For years Wairarapa's sole resident magistrate, he blocked the licence for Morrisons Bush Inn because he was tired of being disturbed by drunken shepherds. In 1865 he retired to Woodside, near Greytown, where he and Revans established a sawmill. He died at Woodside on 3 January 1869.
That Smith adapted readily to the colonial environment is demonstrated by his multifarious achievements. Today he is remembered chiefly for his exact sketches and watercolours of early Wellington, the Hutt Valley and Wairarapa. But it is as a surveyor, and a teacher of young surveyors such as Kettle, that his central contribution to frontier society was made. Arguably the best theoretician in the colony, he tackled new problems scientifically, being an early exponent of triangulation. His career is controversial, however, because he planned the city of Wellington, which is notable for its poor design. Wellington's topography made nonsense of the company's scheme. In accordance with his instructions, Smith tried first to ensure that every holder of a land order obtained one town acre, and only latterly 'to provide for the future rather than the present'. From a pragmatic viewpoint it was no small achievement to survey two towns in six months, in steep bush and bad weather, with inadequate staff and equipment, and amid Maori protest, settler complaints and skulduggery by William Wakefield and his cronies. 'In due time', Revans wrote, 'the difficulties of his task will be his exoneration.'
In addition to his practical surveying work, Smith's reports of his exploratory journeys and surveys have significance for their record of colonial conditions. He noted land-forms and human activity, such as new modes of dressing flax by Manawatu Maori. As a Wairarapa pastoralist he helped to establish New Zealand's wool and beef industry, importing stock from New South Wales. Essentially a scholarly gentleman, religious, and diffident until toughened by Wakefield's deviousness, Smith commanded respect from his fellow settlers. He made a path for others.