James John Patterson was born in New Plymouth on 17 October 1859. His father, George Patterson, an engineer, had emigrated to New Zealand with his wife, Elizabeth, in the Katherine Stewart Forbes in 1852 and established a steam sawmill in the Grey district, outside New Plymouth. After Elizabeth Patterson's death in 1854, George Patterson returned to England to marry Susannah (Susan) Hewitt. James was the fourth child of this marriage.
In March 1860, during the first Taranaki war, the family was forced to seek refuge in New Plymouth; their sawmill and house were destroyed. George Patterson joined the Taranaki Militia, and was ambushed and killed near his own land on 28 February 1864. The same year, Susannah Patterson died of typhus, leaving six young orphans. Although they were Anglicans, the children were assigned to the guardianship of a childless Methodist couple, William and Elizabeth Burton, from whom they had a hard upbringing.
James Patterson received scant education; it was finished by 1867 when, in his ninth year, he was allowed to join a cutter sailing to Pelorus Sound in the South Island – a 'pretty rough and rigorous time'. On the return trip he fled the ship at Opunake and walked more than 3O miles home to New Plymouth through the bush and fern. At the age of 12 he and his 15-year-old brother George drove mobs of cattle south to sales at Hawera; for three nights they camped rough in often unfriendly Maori territory.
Patterson was apprenticed as a blacksmith in New Plymouth in late 1873 or 1874. He later moved to Patea in South Taranaki, working for William and Daniel Williams, blacksmiths and coachbuilders, and established his own forge in the infant town of Manaia about 1882. In 1886 he took part in the fight at A. J. Hastie's farm, part of the Maori passive resistance to European settlement in the area. He married the Williams's sister, Catherine (Kate), a teacher and devoted Methodist, at Patea on 28 September 1888; they had eight daughters.
Patterson diversified from blacksmithing into farming and road contracting. By about 1900 he had begun buying land in Taranaki, on which he established dairy farms. He employed sharemilkers, many of whom stayed with him for long periods. He arranged their harvesting and used his home farm on the Manaia coast to winter replacement stock and breed draught-horses. His progress towards being a large landowner was steady; new ventures were set up once the previous one began paying.
Early in 1914 Patterson, in partnership with a man named Candy, purchased 1,600 acres of swampy, scrub-covered land near Tatuanui in Waikato. He later bought Candy out and supervised the clearing of the land. It was then subdivided into dairy farms. When the New Zealand Co-operative Dairy Company refused to build a dairy factory in the area, Patterson began establishing one himself. The company, realising it was encouraging competition, then built its own. Patterson eventually owned more than 35 farms with some 4,000 cows. At his death his estate was valued at £167,166.
The scale of Patterson's farming operations made his name well-known in New Zealand in the early twentieth century. He had built up his landholdings from nothing by combining a flair for business with a remarkable capacity for hard physical work. He was regarded as a tough man, but fair in his dealings with others. In 1913 he helped load farm produce onto ships in Wellington during the waterfront strike. In spite of being so widely known he held only one public office: a term as director of the Riverdale Co-operative Dairy Company. Catherine Patterson died in 1929; James Patterson died at Manaia on 6 August 1937.