The fighting effectively removed Ngati Toa from Ngai Tahu territory.In late 1836 or early 1837, at Tuturau, Taiaroa was part of the Ngai Tahu war party that destroyed the war party led by Te Puoho-o-te-rangi, of Ngati Tama. Te Puoho, an ally of Te Rauparaha, had travelled down the West Coast and crossed through Tiori-patea (Haast Pass), before capturing the village of Tuturau. Ngai Tahu fugitives reached Ruapuke Island and a well-armed Ngai Tahu war party, led by Tuhawaiki and his nephew, Topi Patuki, marched inland and captured the war party, killing Te Puoho. This Ngai Tahu victory brought an end to the invasions of the South Island by tribal armies from the north.In the 1830s Taiaroa did not always enjoy good relations with the whaling communities on the Otago coast. At times he harassed the whalers of Waikouaiti, who were protected by Tuhawaiki; it is said that on several occasions he was driven off by gunfire. In 1834, in partnership with Te Whakataupuka, he sacked the Weller brothers' station in Otago Harbour and plundered the whalers' houses. On another occasion Taiaroa's attempt to capture the American brig, Pearl, resulted in his being clapped in irons until the vessel cleared Otago Heads.In 1838 Taiaroa travelled to Sydney, where he sold land, including Banks Peninsula, to John Jones and to George and Edward Weller. His land sales often overlapped with or disregarded earlier transactions, which gave rise to conflicting land claims after 1840. He may have bought military supplies in Sydney, because the following year he was one of those who led a large war party to Cook Strait in an attempt to provoke Te Rauparaha into open warfare. This was unsuccessful but Te Ati Awa in Queen Charlotte Sound, fearing attack by Taiaroa, fortified their village in East Bay.Taiaroa played a major part in the peace negotiations between Ngati Toa and Ngai Tahu after the Wairau conflict of 1843. In a situation of growing tension between settlers and Ngati Toa, Taiaroa appears to have considered an alliance with Te Rauparaha against the Pakeha. He visited Te Rauparaha at Taupo pa, Porirua, and marriages were made to confirm the peacemaking between the two tribes.Although the name of Taiaroa appears on the copy of the Treaty of Waitangi taken to the Otago region in June 1840, he did not sign. He played a leading role in South Island land sales to the Crown, and in February 1840 was one of a party of Ngai Tahu leaders with whom Governor George Gipps tried unsuccessfully to negotiate a treaty. Although he professed friendship with the Pakeha he was generally cautious of settlement. However, the depopulation of the South Island's relatively small communities by disease, and the lessening of Ngai Tahu control over their resources, was weakening the position of the tribe. In June 1844 Frederick Tuckett, a surveyor for the New Zealand Company, persuaded Taiaroa and other chiefs to sell the Otago block for £2,400. Taiaroa and several other Ngai Tahu leaders later travelled to Wellington to protest that they had not received a 10th part of the Otago block, which had been promised as part of the sale agreement. In 1848 Taiaroa ceded his land rights in Canterbury and in 1853 he was a signatory to the Murihiku sale.Taiaroa had several wives. The first, Hine-i-whariua, was the sister of Karetai. In 1840 he was with Tarotaro, who had adopted two of his children, probably from his first marriage; according to the French explorer Dumont d'Urville, Tarotaro had tuberculosis. A third wife was named Mawera. Taiaroa's children included Nikuru, who married Edward Weller, and Hori Kerei Taiaroa.The early death of many Ngai Tahu leaders, especially Tahatu and Tuhawaiki, had brought Taiaroa into a position of greater influence within his tribal group by the 1850s.

In November 1856 he attended the intertribal meeting at Pukawa, Lake Taupo, which elected Potatau Te Wherowhero as the first Maori King. In 1860 he travelled to Auckland to attend the Kohimarama conference of Maori leaders, called by the government after war had begun in Taranaki; he later attempted to mediate in the conflict.On 3 April 1859 Taiaroa had been baptised by a Methodist minister, the Reverend George Stannard, taking the name Te Matenga (Marsden). On the same day he had married Kararaina, the daughter of Ngatata-i-te-rangi, of Te Ati Awa. In his last years Taiaroa set aside 10 acres of land at Otakou and built a church there, although he lived mainly at Pigeon Bay, on Banks Peninsula. He spoke some French and English, as well as Maori. A strongly built man of middle height, he had an aggressive disposition; a weakness for alcohol gravely affected his health. He died on 2 February 1863, at Otakou, and was buried on 17 February at Taiaroa Head. Before his death he counselled his descendants to live in peace with the Pakeha and to observe their undertakings .     By Steven Oliver (Dictionary of N.Z. Biography)