Thomas Alfred Sneyd Kynnersley and his twin sister, Mary Palmer Kynnersley, were born on 14 June 1839 at Uttoxeter, Staffordshire, England, children of Thomas Clement Sneyd Kynnersley, a barrister, and his wife, Eliza Rose Sanders. Thomas entered the Royal Navy at an early age and was commissioned lieutenant in 1860 while serving on the Siren. He served on various ships and finally joined the Orpheus, a steam corvette which had been assigned to the Australia station. Because of ill health, which was to dog him for the rest of his life, Kynnersley was granted long-term leave from the navy. He settled at Pelorus Sound, New Zealand, where until 1864 he spent most of his time fishing.
In April 1864 payable gold was discovered in Marlborough province and the Wakamarina goldrush began. Kynnersley seemed qualified to control the goldfield. He was appointed warden of the Pelorus goldfield in October and a justice of the peace the following January. The goldrush to the West Coast started in November 1864. Claims at Wakamarina became deserted, and within a month Deep Creek and Canvastown retained fewer than 500 men. Soon Marlborough's goldfield staff consisted of Kynnersley and one policeman.
Kynnersley transferred to the West Coast in 1865, following his appointments as warden of the Nelson goldfield and resident magistrate at Cobden in November of that year. His district ran from Karamea to the Grey River, which divided the Nelson goldfield from the West Canterbury goldfield. Diggers who crossed the river were required to take out separate miners' rights, while businesses required further licences. Inevitably there was some friction between Kynnersley in Cobden and Warden W. H. Revell in Greymouth, for a navigable river did not make a satisfactory boundary. As the rush extended, Kynnersley retained his headquarters at Cobden, while keeping control over the hordes of men prospecting and working in the Grey and Paparoa ranges.
In 1865 William Fox, an Otago prospector who had been working the coastline to Westport, suggested to Kynnersley that they make a prospecting trip together up the coast. Kynnersley agreed to the proposal for he wanted to know if any rivers in the area were navigable. On 9 May 1866 Kynnersley and Fox chartered the small river steamer Woodpecker and, accompanied by 18 other prospectors, proceeded north. Eventually they anchored off a small bay near Seal Island. At the mouth of the Potikohua River (renamed Fox River) gold was found in payable quantities and another rush began. Some 300 men were scattered from Fox River to the 'pakihi' (an area of grasslands, later the site of Charleston). Initially very little gold was offered for sale, and it was rumoured that the goldfield was a 'duffer'. However, as more claims became profitable the rush gained momentum. Kynnersley moved his administration offices to the goldfields town of Brighton.
Provisioning the pakihi area was difficult: supplies had to be dumped at Woodpecker Bay, 12 miles to the south. But in September the captain of the 13 ton ketch Constant brought his vessel safely into a small cove further up the coast. During November Kynnersley laid out a township near the cove, which had been named Constant Bay, and soon had a number of men clearing and draining the streets. In January 1867 this settlement was named Charleston. The local population was estimated at 3,000. Kynnersley, after a journey to the Inangahua area, now spent his time between Charleston and the larger settlement at Brighton. He later shifted to Westport, having established a warden's court at Charleston. His duties increased when in April 1867 there was another rush to Addisons Flat, near Westport. For nearly three years Kynnersley, with George 'King' Sale, who administered the area south of the Grey River, controlled an erratic population of over 25,000, scattered across some 7 million acres of auriferous country.
Kynnersley was a capable administrator and conscious of the dignity of his position. During December 1867 articles were published in the Westport Times under the pseudonym 'Bohemian'. One item remarked on Kynnersley's attendance at the Charleston races in the company of two women who were not considered 'respectable'. Kynnersley promptly turned up at the Times office brandishing a riding-whip, and demanded to see 'Bohemian'. The culprit was forced into a back room, knocked down and severely hammered. The next day the Times carried a brief reference to 'our late editor'. Kynnersley was charged only costs at the resultant court case.
In January 1867 Kynnersley was appointed chief warden and commissioner of the Nelson South West goldfield by the Nelson provincial government at a salary of £700 a year. He was given full control of the goldfield and power to spend monies on public works. He enjoyed considerable popularity. One Nelson provincial councillor pointed out that it did not necessarily have anything to do with his personality, for any man who had £40,000 or £50,000 to spend as he liked on the West Coast could not fail.
Early in 1868 conflict arose between loyalist Irish in the district and those sympathetic to the Fenian cause. On St Patrick's Day 600 men, mostly from Addisons Flat, marched in a procession through Westport to the cemetery. They wore black and green to show respect for three Fenians recently hanged in Manchester gaol. After listening to 'some extremely objectionable and inflammatory speeches' expressing dissatisfaction with the government, the group dispersed. The Westport Volunteer Rifle Corps offered the services of 150 men should any trouble arise, but Kynnersley decided to ignore the incident.
On 2 April, a public holiday proclaimed to commemorate the failed assassination attempt on the Duke of Edinburgh in Sydney, a loyalist rally took place at Westport. On 3 April news reached Westport that those loyalists from Addisons Flat who had attended the gathering at Westport had been attacked on returning home. Westport newspapers printed misleading accounts which stirred up grievances between Irish factions. At Addisons Flat rumours spread that the Westport Volunteers were coming to attack the people. A large crowd prepared to meet them, armed with any weapons they could find. A riot allegedly took place, in which Orangemen were compelled to retreat to a swamp about two miles from town. The arrival of Kynnersley, who rode his horse into the fray, calmed the situation and hostilities ceased. After all this, reported Kynnersley, 'three cheers were given for "Law and Order" and the majority of those assembled gradually dispersed'. Kynnersley called a public meeting to discuss the recent events. In spite of the success of this gathering, Westport newspapers, notably the Westport Times, continued to publish items claiming that Addisons Flat was controlled by 'a disordered mob of ruffians' and that a reign of terror existed. It was only Kynnersley's tact which kept the 'miserable street row' under control.
Kynnersley's popular image was founded on various accounts of his ingenuity and daring. The story is told that in 1868 John Blackett (the Nelson provincial engineer), Arthur Dudley Dobson (his assistant and the discoverer of Arthur's Pass) and Kynnersley were having a meal in a combined store-hotel at Punakaiki when suddenly revolver shots and shouting were heard. They watched as a woman with a revolver in each hand chased a man around the crowded tents outside. The woman, Mrs Jarvis, came up to the trio and began to threaten them. Kynnersley said, 'We must stop this, and as I am the only bachelor of the party I will try first.' He addressed Mrs Jarvis and offered to listen to her problems over a drink. She followed him into the bar where brandy was put by her right hand. She put down the revolver to pick up the glass. Another brandy was placed by her left hand, at which she put down the other revolver and took up the second glass. Kynnersley then snatched up both revolvers and left the bar.
Towards the end of 1868, because of continual ill health from tuberculosis, Kynnersley resigned all his official positions. He left for Melbourne in January 1869 and probably travelled on to England. While he was away he resigned from the navy. On returning to New Zealand in February 1870 he was appointed resident magistrate, justice of the peace, and warden of the Nelson South West goldfields, which now included the upper Motueka area. In March 1870 he became a member of the Nelson Provincial Council and in June was elected to the House of Representatives as member for Westland North (Buller).
Kynnersley died in Nelson on 1 February 1874, aged 34 years. His early death deprived New Zealand of an extremely able administrator. He was buried in Nelson cemetery, where he lies beside other pioneers of the West Coast: explorer Thomas Brunner, storekeeper Reuben Waite, and prospector George Fairweather Moonlight. Two mining camps were called Kynnersley, as was a gold lead on Addisons Flat. The Kynnersley Ward at Buller hospital, and the Kynnersley Domain at Mokihinui, are two memorials which are still in existence.