Jeanie Collier was born probably in 1791 or 1792, at Monimail, Fife, Scotland, one of a family of seven children. Her father, Robert Collier, was a soldier, who had served in Holland with the 94th Regiment of Foot. His wife, Antonia Ewing, was from Yorkshire. Little is known of Jeanie Collier's early life. As a young woman she lived with the rest of her family at Ardock Cottage, Cardross; later she had her own household at Baile Bruiche, Dunoon. She remained single.
In 1854 one of her married sisters, Leslie Thomson, who had been widowed in 1842, died leaving four sons. The same year the resourceful Jeanie Collier, now in her early 60s, brought three of her orphaned nephews to New Zealand, via Australia. They were Leslie Collier, aged 18; James Elliot, aged 16; and Andrew, aged 14. The eldest brother, Robert James, aged 21, was excluded from the emigration plan by his disapproving aunt because of his dissolute habits. Jeanie's brother, James Collier, who was aged about 40, came too. He was probably backward: she managed his affairs and left him an annuity but did not buy land for him.
In order to provide her nephews with occupations, Jeanie Collier took up land in South Canterbury, becoming the first recorded woman runholder in New Zealand. In November 1854 she applied for runs No 35 and No 36, which took in Crown waste lands from the Otaio River south to the Hook River. The pastoral licence issued on 1 February 1855 charged an annual rental of £7 2s. 6d.; each run comprised 28,500 acres and was estimated to carry 7,125 sheep, or cattle in proportion. She also bought some sections near the main area of land, which was known as Otaio station. In 1856 Run No 36 was transferred to Leslie Collier Thomson.
Initially Jeanie Collier's nephews prospered on their aunt's well-chosen landholdings. In 1908 James Thomson wrote, 'it would be impossible to find a more perfect country for stock.' However, Jeanie Collier, no longer young and fit, found living conditions primitive. On arrival at Timaru she was driven south in George Rhodes's bullock dray to her unsurveyed runs. The driver followed the rough coastal track, then travelled inland, using prominent western landmarks for his bearings. Once at Otaio, Jeanie Collier slept in a tent until the first permanent house, a small slab hut thatched with tussock, was built. Occasionally when she woke in the morning she found that the intense cold had frozen her nightcap to her pillow. Life was lonely, and her isolation intensified when she became blind. She found some companionship when her younger, widowed sister, Margaret Hyde, and her nephew, George Hyde, came to live at Otaio. The nearest neighbours lived some 10 miles away.
Ever practical, one day Jeanie walked from the house to a gentle slope leading to a small creek and stuck her walking-stick in the ground, saying: 'When I die, this is where I wish to be buried.' On 16 September 1861, after five years of caring for and advising her nephews, Jeanie Collier died and was buried according to her wishes. In her last years she had, in spite of her age, capably managed both money and land. Ironically, within a few years her nephews had sold all the land they had acquired through her. Leslie and Andrew Thomson failed financially in the 1860s and left the country. James Elliot Thomson remained in New Zealand.