Te Ngahuru was born at Te Purenga, in Rūātoki, the elder of the two sons of Pāhiko (his father) and Kau (his mother). He inherited the fighting characteristics of his ancestors, Haokitahā, Tūwhenuakura, Rōmaiwharerākau and Kōurakino, who, in their time, were the scourge of the Waimana, Ōhiwa and Rūātoki districts. He was raised partly in Rūātoki and partly in Ruatāhuna, although he spent most of his life in Rūātoki. He came into prominence through his marriages, particularly to Te Utu and Kūmara, whose hapū affiliations allowed a wide range of alliances to be established.
The tribal name that has been adopted by the descendants of Te Ngahuru is Ngāti Koura, although it would have been more appropriate to have used Te Ngahuru's name as the ancestor. Of his ancestor Kōurakino, little is known except that he belonged originally to Ngāti Te Ehutū, more commonly known as Te Whānau-a-Te-Ehutū, a branch of Te Whānau-a-Apanui tribal group.
Te Ngahuru and his contemporary Te Rangimōwaho were regarded as two of the greatest warriors of the Rūātoki, Waimana and Ruatāhuna districts. Te Ngahuru was taught in Mairerangi, the famous whare wānanga of Tūhoe at Te Honoi, between Rūātoki and Ruatāhuna. As a pupil of Te Whatupe, Taokaki and the noted tohunga Tauaiti, he was well versed in tribal history and traditions. He involved himself in many disputes, some of his making, some where he had been requested to offer assistance, and others which he simply made 'his business'. By nature he was sometimes very short-tempered, and at other times kindly or reclusive. People seeking his assistance or advice always approached him cautiously, not knowing the reception they were likely to receive. He was famed for his skill in the use of various weapons, in particular the taiaha.
Around the year 1800 Tūhoe experienced a good deal of warfare, both between Tūhoe hapū and between Tūhoe hapū and other tribes. Te Ngahuru rose to prominence in this period. The battle known as Whatawhatatū, at Rūātoki, was important because of the way in which various leaders realigned their tribal alliances. Ngāti Rongo, a hapū of Tūhoe, applied to their kinsfolk of Tamakaimoana, in Maungapōhatu, for assistance in attacking the large Ngāti Raka hapū of Tūhoe, who were then occupying lands now known as Ōpouriao and Rūātoki. Ngāti Rongo chiefs Te Rohi and Te Au-ki-Ōhiwa were killed by Ngāti Raka people; however, Ngāti Rongo of Tūhoe sought a much greater defeat of their relatives than simply avenging the two chiefs. Te Rangimōwaho, who was both Ngāti Rongo and Te Mahurehure, applied to Ngāti Koura for assistance. Te Ngahuru did not join, although his relatives, Te Raha and Tohiāmanu, did.
Te Rangimōwaho made his approach to Ngāti Koura by means of an appeal for assistance in war. He took his cloak, a horihori with twisted black strings, and burned several holes in it, spoiling the garment. Then he travelled to a pre-arranged meeting place, known as Ōtamahaka, and there found Te Ngahuru, Te Raha and Tohiāmanu. Te Ngahuru immediately knew the object of Te Rangimōwaho's mission. The cloak was placed on Te Raha's shoulders and by allowing the garment to remain there for some time, he signified that he would assist in battle. Tohiāmanu then placed the cloak on his shoulders, indicating he would also wear the trappings of war. For reasons known only to himself, Te Ngahuru did not show himself willing to participate. The battle that took place at Whatawhatatū was followed by a defeat for Ngāti Raka at Ōtenuku, so severe that they left Rūātoki for ever and lost their tribal lands to the hapū of Tūhoe still living there.
About the year 1821 Te Ngahuru took his people, Ngāti Koura, to Raehore pā on the banks of the Mangaōrongo Stream at Ruatāhuna to prepare for an expected invasion by Te Arawa. While there he killed Rangiruru of Ngāti Rongo. Ngāti Rongo sought vengeance, and Te Ngahuru's relative, Titi, was slain. About 1823 he returned with his people to Rūātoki, occupying Te Kōau pā at Waikirikiri in the south. He also took part in the killing of some Te Whakatōhea people on the eastern boundaries of the Rūātoki Valley. This led Te Whakatōhea and the former inhabitants of the Rūātoki lands, Ngāti Raka, to march against Tūhoe at Te Kōau pā. These retaliatory raids also involved Ngāti Rongo, Ngāti Tāwhaki and Ngāi Tūranga hapū, who were defeated by Te Whakatōhea and Ngāti Raka at Te Kōau and Ōtairoa. At Ōtairoa Te Ngahuru's father, Pāhiko, was killed, and many Tūhoe women were captured and carried off to Ōpōtiki. The women were of high rank: among them were Hinekura, wife of Te Purewa; Mamaka, wife of Te Umuariki; Te Mihinga; Matarau; and Tirahaere. Most were released and returned to Rūātoki. But the defeat of Tūhoe was a severe blow, and the Rūātoki hapū sought to avenge the Ōtairoa defeat. Te Ngahuru led a party of the related hapū of Ngāi Tūranga, Ngāti Rongo, Te Urewera and Ngāti Koura to the Waimana Valley and attacked Ngāti Raka at Tīwhana. The two senior chiefs of that tribe, Te Moanawaipū and Rangitūmatarau, were slain. Then, at the battle known as Te Pou-o-Urutake, Ngāti Raka were completely expelled from the Rūātoki and Waimana areas. Remaining Ngāti Raka, related to and intermarried with Tūhoe hapū, do not have any mana under that tribal name.
After the battle Tapoto, the leader of Ngāti Raka, saw very little chance of regaining lands that had been lost, and so took part in peace negotiations. He stayed at Rūātoki for some days, visiting Te Ngahuru at Ōtamahaka pā. Tapoto gave Te Ngahuru a friendly warning: 'Remain here at our home. I am returning to Ōpōtiki. After I am gone, do not accompany any war parties to the east.'
Te Ngahuru's influence over the destinies of Tūhoe people at Rūātoki and Ruatāhuna continued. He was very friendly with another influential chief, Te Kea, and his son, Te Aho, who belonged to Ngāti Rongo. Paiterangi of Ngāti Rongo decided to kill Te Kea because of some previous offence. However, he was killed by Te Kea and his body buried in a swamp. Ngāti Rongo sent a second party and this was successful in killing Te Kea. Te Ngahuru and his younger brother, Te Kauanga, went to Te Tawa in Rūātoki, and slew a Ngāti Rongo chief called Te Hiakai, as an act of blood vengeance. While returning home, they encountered Te Wahamīanga, who was killed by Te Ngahuru. Two people had now been slain to equalise the death of Te Kea, as a mortuary sacrifice. There was much talk of revenge, but as Te Ngahuru had a numerous following and was a member of several hapū, nothing came of it.
Te Ngahuru's success, especially in the battles against Ngāti Raka, remains significant. The territories which are now claimed by Tūhoe as confiscated lands are those areas in which Tūhoe hapū were involved in conflict with Ngāti Raka. The period is crucial to the Tūhoe claim in establishing the territorial sovereignty which it had prior to the confiscation of land in January 1866 under the New Zealand Settlements Act 1863. When the Urewera Commission held its sittings in the Tūhoe area after 1896, Ngāti Koura claims to land were often based on the places where Te Ngahuru lived and the extent of his mana during his lifetime. One of the most important pā in the Rūātoki district, which Te Ngahuru occupied, was Te Tapuwae. It was decided, after the battle of Ōtenuku, that this pā would be used as a burial place for chiefs. Te Tapuwae remains the most important burial place in the Rūātoki district; by 1955 it had become too crowded for further burials. Any chief who was in command of this pā was generally regarded as possessing great military prowess, and as influential in tribal decision making.
Te Ngahuru spurned the use of firearms, although recognising their destructive power. When the Ngāpuhi invasion took place, it was obvious to him that his people would suffer great losses if they did not retire into the safety of the forests at Ruatāhuna. During this period the planting of maize began in the fertile soil of Ōpouriao and Rūātoki. This suggests that while Te Ngahuru found some novelties were unacceptable, others such as food, clothing and cooking utensils were seen as useful. Te Ngahuru, although steeped in the traditions of his people, was by nature receptive to new ideas.
The exploits of Te Ngahuru's children also provided the basis for the settlement of hapū, in particular Rūātoki and Ruatāhuna. His son, Piki, was a famous fighter and bard. Another son, Te Ahoaho, became a fighting chief, a highly respected tohunga and historian of both Ngāti Koura and Te Urewera hapū. From his daughter, Te Kura, came the descendants who have been vested with the mauri of the meeting house at Mātaatua in Ruatāhuna, known as Te Whai-a-te-motu. This house was built for Te Kooti Arikirangi in 1888. Te Ngahuru's third son, Waiari, gained a reputation as a fearsome fighter, but his fame has been overshadowed by that of his older brothers and of his son, Tamarau Waiari.
Three tribal aphorisms are credited to Te Ngahuru. It is said that when asked whether he would assist in battle against Ngāti Raka, he replied: 'Ko Ngāti Koura tēnei, he kiri kawa ki te rākau' (I am of Ngāti Koura, we are ever sensitive to weapons raised against us). In another, he said: 'Kei takahia te pae hiwi o te Tāhū-o-Haokitahā' (Do not presume that the Haokitahā ranges are open territory). This was a warning that his mana extended from the Rūātoki Valley into Waimana and anyone crossing through his territory would need his approval. The third saying is similar to the first, but uses an expression peculiar to Tūhoe: 'Ngāti Koura touareare' (Ngāti Koura ever ready to participate in battle).
Te Ngahuru died possibly in 1823, at the time when Pōmare I and his Ngāpuhi war parties were invading the Urewera. His death is recorded as having been the result of influenza during an epidemic, at Ōhāua-te-rangi, north of Ruatāhuna, on the banks of the Whakatāne River. He is buried there and his grave is known to several Tūhoe historians. It is used as a chronological aid in determining the occurrence of events in Tūhoe history and the location of tribal boundaries.