Te Rangihaeata, born probably in the 1780s in the Kāwhia district, was a leader of Ngāti Toa. His hapū included Ngāti Kimihia to which he was kin through his mother, Waitohi, who was the elder sister of Te Rauparaha. Through his father, Te Rākaherea, he was a junior relative of the senior Ngāti Toa leaders in his generation, Te Pēhi Kupe and his son, Te Hiko-o-te-rangi of Ngāti Te Maunu.

Te Rangihaeata's youth was dominated by a struggle between the peoples of Kāwhia and other Waikato districts for control of the fertile but sparsely populated coastland towards Raglan. In one incident early in the nineteenth century several of Te Rangihaeata's sisters were killed by the Waikato tribe Ngāti Pou.

In 1819, already regarded as a war leader of his people, Te Rangihaeata joined Te Rauparaha on a joint war expedition with Hokianga and northern Kaipara people; they travelled through Taranaki to the west coast region of the southern North Island. Te Rangihaeata assisted in the taking of the Ngāti Apa pā, Pūrua, in the Whanganui area. A running fight then developed down the coast from the Turakina River to Rangitīkei and Ōroua during which Ngāti Apa chief Te Arapata Hīria and his sister, Te Pikinga, were captured. The expedition then passed on down the coast, taking their captives with them. In the next few months Te Rangihaeata was involved in killing or capturing many people on the Kapiti coast, at Te Whanganui-a-Tara (Wellington Harbour) and in Southern Wairarapa.

Te Rauparaha and Te Rangihaeata returned to the west coast of the North Island by canoe, landing at Te Pou-a-te-rehunga, north of the Rangitīkei River. In a bid to make peace with Ngāti Apa, Te Rangihaeata sent Te Arapata Hīria and Te Rātūtonu, the Taranaki husband of his sister, Topeora, into the Ngāti Apa pā, Te Awamate. According to Ngāti Apa sources a peace alliance was concluded. He took Te Pikinga as a wife of chiefly status, and she was given the gift of a slab of greenstone called Te Whakahiamoe, which was afterwards made into adzes.

Taking Te Pikinga with them, Te Rangihaeata and Ngāti Toa returned to Kāwhia. After some serious defeats by Waikato, Te Rauparaha suggested migrating to the Kapiti coast. In 1821 Te Rangihaeata accompanied the first section of the main Ngāti Toa migration, called Te Heke Tahu-tahu-ahi, southwards. Te Rangihaeata's infant son, Te Kāuru, was drowned when their canoe capsized while crossing the Mōkau River so that Te Rangihaeata was later known by the alternative name of Mōkau. About 1822 Te Rangihaeata helped defeat Waikato at Motunui in Taranaki.

Ngāti Toa and their allies continued their southwards migration under a different name, Te Heke Tātaramoa, in 1822. They were met at Waitōtara by some Ngāti Apa relatives of Te Pikinga, who escorted Te Rangihaeata, Te Rauparaha and their people on to Whanganui and Rangitīkei. Te Rangihaeata agreed that Ngāti Apa should remain unmolested on their land and left Te Pikinga for a period at Rangitīkei as 'he pou rohe', the embodiment of his authority, or mainstay, within the region. Te Rangihaeata and Te Rauparaha were anxious to settle in peace, but their kinsman Nohorua killed a Muaūpoko woman, Waimai. In revenge, Muaūpoko killed members of Te Rauparaha's family at Papaitonga. Te Rangihaeata took part in the subsequent campaign, and later moved with Te Rauparaha to Kapiti Island. While Te Rangihaeata fought the tribes on the mainland he continued to protect those Ngāti Apa hapū living north of the Rangitīkei River; however, he took part in the attack on Hotuiti pā, in the Manawatū district, in which a number of southern Ngāti Apa had joined Rangitāne defenders. Te Pikinga was sent in to attempt to negotiate the withdrawal of Ngāti Apa, but failed. The pā was rushed and taken.

About 1824 Te Rangihaeata, Te Rauparaha and a small number of their people successfully defended Kapiti Island against the attack of nearly 2,000 enemies from the Kapiti coast, Te Whanganui-a-Tara, Wairarapa and the northern South Island. After this battle Te Rangihaeata, angry at Ngāti Apa's perfidy in joining the enemies of Ngāti Toa, attacked Pikitara pā near the Rangitīkei River. The 400 defenders led by Tūrangapito and Te Hākeke fled in fear of Ngāti Toa's few muskets. Te Rangihaeata took a full part in the subsequent seven years of struggle between Ngāti Toa and the local tribes.

Also about the year 1824, the Ngāti Ira family of Tāmairangi were captured by Ngāti Mutunga at Ōhariu; Tāmairangi, believing she was about to be killed, sang a lament so haunting that Te Rangihaeata, who was visiting Ngāti Mutunga, was moved to extend his protection to the family, taking them with him to Kapiti Island. Te Kēkerengū, son of Tāmairangi, was believed to have abused Te Rangihaeata's hospitality by seducing one of his wives; he and his family took refuge in the South Island with Rerewaka of Ngāti Tūteahunga, a section of Ngāi Tahu. Rerewaka cursed Te Kēkerengū's pursuers, and it was partly this curse that led Te Rauparaha and Te Rangihaeata later to devastate the Kaikōura Coast. From there Ngāti Toa went on to Kaiapoi, where Te Pēhi Kupe was killed. Te Rangihaeata probably took part in the three subsequent campaigns against Ngāi Tahu in the South Island, in 1830 on the brig Elizabeth, in 1831 against Kaiapoi pā, and in the mid 1830s, on the South Island's northern coast including Golden and Tasman bays.

In the 1830s Te Rangihaeata lived on Mana Island, although he often spent time on Kapiti and visited the mainland. He had cultivations at Taupō, Porirua. Shore-whaling stations established from 1827 provided a regular supply of muskets and powder, together with tobacco and spirits. Early in the 1830s a small whaling station was established on Mana Island, and from 1835 John Bell had a sheep and cattle run there.

The authority of Te Rangihaeata and Te Rauparaha depended on their continued strength, and on their skills in reconciling conflicts among their migrant allies, and between them and allied local tribes. After Ngāti Raukawa's arrival in three migrations in the late 1820s, Te Rauparaha had permitted them to settle in the Ōtaki, Manawatū and Horowhenua areas. Te Rangihaeata, who, through his marriage with Te Pikinga, retained mana over the area north of the Rangitīkei River, gave certain hapū permission to occupy land there. Ngāti Apa later regarded Te Rangihaeata's mana as the most important factor preventing their enslavement by Ngāti Raukawa.

In 1834 the balancing act was to fail; Te Āti Awa attacked Ngāti Raukawa at Haowhenua, Ōtaki, and a general war developed. Te Rangihaeata supported the Ngāti Raukawa side because of their links to him through his grandmother, Parekōwhatu. Other factions of Ngāti Toa, notably Te Hiko-o-te-rangi and Ngāti Te Maunu, supported Te Āti Awa. Te Rangihaeata permitted another large group of Ngāti Raukawa to settle in the Rangitīkei area after Haowhenua.

Following Haowhenua a group of Ngāti Tama came from Wairarapa to the Kapiti coast and camped at Paremata. Te Rangihaeata, Te Rauparaha, their Ngāti Kimihia followers, and a part of Ngāti Raukawa drove them to Ōmanga-rau-tāwhiri. After a year Ngāti Tama made an attempt to capture Mana Island itself. Te Rangihaeata forcibly expelled them to Ōhariu. Annoyed at their persistence, Te Rangihaeata said their leader, Te Kāeaea, must have dog's ears, since he was so obdurate; Te Kāeaea was henceforth known as Taringakurī.

Te Rangihaeata was feared and disliked by the whaling communities living under his aegis. He exacted tribute in the form of numerous demands for the gifts he considered they owed him for his tolerance, demands which the whalers saw as extortion and bullying. Europeans who encountered him in the late 1830s or 1840s tended to regard him as Te Rauparaha's 'fighting general' or as his lieutenant. Te Rauparaha was credited with the greater cunning, but Te Rangihaeata was thought to be more ferocious.

Te Rangihaeata's mother, Waitohi, died late in 1839. Te Rangihaeata erected a mausoleum to his mother's memory; it was later recorded in a painting by George French Angas. During the prolonged tangi held for her on Mana Island, Ngāti Raukawa irritation at Te Āti Awa re-emerged, culminating in their attack on Waimea pā at the battle of Te Kūititanga, Waikanae. Once again Te Rangihaeata supported Ngāti Raukawa.

In October 1839 the New Zealand Company ship Tory brought Colonel William Wakefield to the Kapiti coast to purchase land for European settlement. He induced Te Rangihaeata to sign, on 28 October 1839, a deed purporting to purchase all his rights and claims on both sides of Cook Strait. Te Rangihaeata intended to give Europeans the right to occupy certain specific areas such as Nelson. Later this deed and others were invalidated; they were inadequately translated or explained, and far too sweeping in their description of territories 'purchased'. On 19 June 1840 Te Rangihaeata signed the Treaty of Waitangi on board the Herald. He probably intended to do no more than accept a governor to rule over the turbulent whalers and keep the company settlers in check.

Gradually, during 1840–41, Te Rangihaeata learned that in European terms 'land purchase' meant permanent alienation of land, and that his signature on the treaty transferred more than mana kāwanatanga over the whole country to the British Queen. For the rest of his life Te Rangihaeata was an angry man, totally opposed to the erosion of his authority by means of the creeping European disease of land purchase. When Te Whatanui of Ngāti Raukawa sold a portion of Manawatū to the company, Te Rangihaeata travelled about the various pā arguing with those who had agreed to its sale. He objected to the company's claim to have purchased Porirua, and opposed the efforts of the surveyor, C. H. Kettle, to survey the area in April 1841. In June 1841 he ordered some of his followers to block the bridle path to Porirua by felling trees and destroying bridges. Rendered insecure by William Spain's investigation of New Zealand Company purchases, many settlers blamed Te Rangihaeata for most of their woes; a public meeting held in Wellington demanded his arrest; Police Magistrate Michael Murphy prudently refused to prosecute him.

Late in 1842 the New Zealand Company turned its attention to expansion from Nelson into the Wairau Valley. Te Rangihaeata and Te Rauparaha consistently denied that Wairau had ever been sold. The land commissioner was due to investigate the company's claim in June 1843, but in April surveyors erected a hut on the land. Te Rauparaha and Te Rangihaeata, having carefully laid aside the movable property of the surveyors, burnt the hut down. Captain Arthur Wakefield obtained warrants to arrest them on charges of arson, and on 17 June he, Police Magistrate Henry Thompson and an armed force of 47 European 'special constables' went to Wairau to execute it. In the ensuing confrontation a stray shot killed Te Rangihaeata's wife, Te Rongo, as she sat by the fire. Volleys were exchanged and the settler force retreated. Captain Wakefield ordered the firing to cease and surrendered, displaying a white handkerchief in token of peace. Nine Europeans were made prisoner. Te Rangihaeata demanded that they should be killed. When Te Rauparaha objected, Te Rangihaeata reminded him of Te Rongo's death. Te Rangihaeata then silently moved behind each prisoner and clubbed them to death.

Furious demands by the settler population for his arrest and execution, and his own expectation that the government would seek revenge, led Te Rangihaeata to move to Taupō, Porirua, where he built a new pā. He received unexpected support from Governor Robert FitzRoy; FitzRoy rebuked the Nelson magistrates for issuing warrants, explaining that persons who burnt their own property could not be charged with arson, and affirming that the Wairau Valley had never been purchased. At Waikanae, he rebuked Te Rangihaeata and Te Rauparaha for killing the prisoners, but said that as the Europeans were first in the wrong, he would not avenge their deaths.

Te Rangihaeata also opposed the spread of settlement in the Hutt Valley, claiming that the area had not been paid for. Ngāti Rangatahi, originally from Whanganui, had assisted Ngāti Toa in their years of struggle, and had been granted rights of occupation in the Hutt in return for gifts of tribute, birds and other produce. In 1841 and 1842 Te Rangihaeata and his uncle encouraged Ngāti Rangatahi under Kāparatehau and Ngāti Tama under Te Kāeaea to settle and cultivate there. Te Rangihaeata consistently took the view that the sale of the Hutt by Te Āti Awa was invalid without his consent. Governor William Hobson, while awaiting Commissioner Spain's decision on the Hutt, had permitted European squatting. In 1844 Spain decided that further compensation would validate the purchase of the Hutt, and £1,500 was eventually distributed. Te Rangihaeata's name was forged on the deed of sale by his nephew Matene Te Whiwhi in a misguided attempt to speed settlement. At this time Te Rangihaeata suggested that he would agree to the Hutt's sale if certain reserves in Upper Hutt were set aside for Ngāti Rangatahi.

A degree of coolness developed between Te Rangihaeata and Te Rauparaha, who had offered to give up the Hutt without Te Rangihaeata's agreement. Governor FitzRoy and others continued to attempt to arrive at a negotiated settlement; in March 1845, after discussion of the issues with Te Rauparaha at Ōtaki, Te Rangihaeata consented to regard the dispute as between Ngāti Rangatahi, Ngāti Tama and the government, but made it clear that he would not persuade the Māori to leave the Hutt. He accepted his share of the company's extra compensation, but sent word to Ngāti Rangatahi that he would support them if they were attacked by the Europeans.

From this point the situation deteriorated. The Māori occupants refused to leave; the Europeans constructed forts. During Te Rauparaha's attempt to persuade the Māori to leave in May 1845, Te Rangihaeata camped with 500 or more followers in the upper Hutt Valley. After the arrival of Governor George Grey with 500 troops in 1846 Ngāti Tama reached a separate agreement; the governor's subsequent negotiations were with Kāparatehau. He agreed to withdraw by 25 February 1846, but settlers moving in looted the houses of the Māori, their church and plantations. When the CMS missionary Richard Taylor encountered Te Rangihaeata at Porirua the chief reproached him with this perfidy but said he had sent an angry letter to Kāparatehau telling him to return the articles he and his people had looted from settlers' houses in revenge. He repeated that if Kāparatehau was given a piece of land all would be well, and he directed Taylor to tell this to the governor. He himself did not wish to fight.

In March Te Rangihaeata was joined at Porirua by a party from Taupō. Governor Grey arrived in the Castor on 9 March with troops in support on the Driver, but Te Rangihaeata refused to meet him. He had heard rumours that the governor was coming to hang him for the Wairau affair. At the time of the Gillespie murders on 2 April 1846 Te Rangihaeata was building a new pā at Pāuatahanui, on the eastern inlet of Porirua Harbour, which was protected from a sea attack by mudflats. By May Te Rangihaeata was regarded as being in arms against the government although at no time did he attack the troops at Porirua or in the Hutt. Kāparatehau was considered to be fighting on his orders, particularly in the matter of the attack on Almon Boulcott's farm on 16 May 1846.

During May and June government officials and the military debated the wisdom of attacking Te Rangihaeata at Pāuatahanui; Grey feared that Te Rauparaha might abandon his neutrality and attack him in the rear. On 23 July Te Rauparaha was captured at Taupō pā, and subsequently government troops and Māori allies advanced against Pāuatahanui; before they arrived Te Rangihaeata abandoned his position and retreated through the Horokiri Valley (also known as Horokiwi). In early August government forces discovered Te Rangihaeata fortified on a hog-backed spur behind a stockade. From this position he was able to inflict a check on government troops; other clashes were fought on 13 August and later that month, after which Te Rangihaeata's party dispersed and escaped.

Te Rangihaeata and his followers eventually settled in a defensible position in the Poroutāwhao swamp near the coast south of the Manawatū River. He had sent letters to various areas, including Waikato, for support, and may even have visited these regions. He did not receive much aid, and in the next few years his people suffered from starvation and want. In 1847 he raided Kapiti Island, but otherwise remained quiescent in his swampy retreat. The governor gave up all idea of attacking him even when he imposed tolls on travellers using the Foxton–Levin beach road. He was induced to refrain from aggressive moves by frequent visits on the part of Lieutenant W. F G. Servantes who had married one of his grand-daughters.

In 1848 Te Rangihaeata was angered by the plans of Ngāti Apa leaders to sell the Rangitīkei block, but was eventually induced by missionary Octavius Hadfield to give his consent. After the north side had been sold, Ngāti Apa attempted to lay claim to the south side of the block by building a hut on it; this was destroyed forthwith by Te Rangihaeata.

In his last years Te Rangihaeata ceased his active opposition to European expansion. Although he himself wanted nothing from the European, disdaining even to wear imported clothing, he told Governor Grey 'that the spirit of the times was for peace, and now men, like women, used their tongues for weapons'. He visited Ōtaki to farewell Grey in 1853, became a church-goer, though not a Christian, and accepted a gift of a horse and gig from the governor, given to induce him to cease charging tolls on the road. He died on 18 November 1855, as a result of pneumonia after lying in a stream to reduce a fever caused by measles; he was thought to be in his early 70s. He was buried at Poroutāwhao beside Te Pikinga.