Known in his youth as Tama-ki-Hikurangi, Kawepō was born at Taumata-o-he pā, at the junction of the Mangatahi Stream and the Maraekākaho and Ngaruroro rivers, early in the nineteenth century. His mother, Te Pakapaka, was of high rank; she was the daughter of Te Uamairangi, and the younger sister of Tūhotoariki, principal chiefs of Ngāi Te Ūpokoiri, of Heretaunga (Hawke's Bay) and inland Pātea, the upper Rangitīkei region. Through his father, Tūmanokia, Kawepō also belonged to Ngāti Hinemanu, and had connections with Ngāti Whiti and Ngāti Tama of Pātea, Ngāti Honomōkai and Ngāti Mahuika. Through his descent from Te Whatuiāpiti, Tāraia I and Whatumamoa, he held great mana over wide areas of Heretaunga and its hinterland.
He received the name Kawepō as a boy when Ngāti Raukawa attacked Ngāi Te Ūpokoiri and Ngāti Hinemanu in Pātea, killing the important chiefs Hoeroa and Te Hīanga. It is said that part of Hoeroa's body was carried to Taupō by night; hence the name Kawepō, which means 'carried by night'. As a youth Kawepō was a witness to the long drawn-out struggle between his people and Ngāti Kahungunu and Ngāti Te Whatuiāpiti, the major tribes of Heretaunga. Ngāi Te Ūpokoiri and their allies were defeated at the battle of Te Whiti-ō-Tū, and took refuge at Taupō. When Tiakitai, the chief of Waimārama and a cousin of Kawepō, passed through Taupō on his way to redeem the Heretaunga leaders taken prisoner by Waikato at the fall of Te Pakake pā about 1824, he invited Ngāi Te Ūpokoiri to return, but most of them feared to do so. Those who joined him included Kawepō and his older sister Mekemeke, later baptised Erena. Mekemeke became the wife of Tiakitai. In 1824 or 1825 a party of Ngāti Te Koherā, kin to Ngāti Raukawa, came and settled near Te Roto-a-Tara, a lake near Te Aute, under Te Momo-a-Irawaru. Kawepō was among Ngāi Te Ūpokoiri who then occupied the island in Te Roto-a-Tara.
Most of Ngāti Te Whatuiāpiti and some Ngāti Kahungunu had retreated to Nukutaurua on the Māhia peninsula to avoid the Waikato invasion. When they heard that Ngāti Raukawa and Ngāi Te Ūpokoiri were in occupation of Te Roto-a-Tara, they came to drive them away. Ngāi Te Ūpokoiri and their allies were defeated; Kawepō was put over a fire. Tiakitai sent his brother Tatere to intervene for Kawepō, who was taken off the fire and turned over to Ngāpuhi allies of Ngāti Te Whatuiāpiti as their captive.
Ngāpuhi took Kawepō to Nukutaurua; he remained with them for more than 10 years. His rank seems to have been respected; he acquired a moko, and gained a reputation as a wrestler. About 1837 he was taken to the Bay of Islands and lived at Waimate North for several years. While there he was converted to Christianity and baptised Rēnata (Leonard).
In 1842 and 1843 Kawepō is said to have accompanied Bishop G. A. Selwyn on his first visitation tour of New Zealand. When he found Ngāi Te Ūpokoiri living under the protection of Rangitāne in Manawatū, he told them they should return to Heretaunga. It may have been on this occasion that Kawepō confronted Mananui Te Heuheu Tūkino II, and demanded that lands claimed by Ngāti Tūwharetoa in inland Pātea should be returned to his people. Kawepō then returned to the Bay of Islands.
In December 1844 Kawepō accompanied the missionary William Colenso to Hawke's Bay in the brig Nimrod. When Colenso's five Māori teachers from Poverty Bay returned home, Kawepō was chosen by Colenso as their replacement in June 1845. For more than four years he carried out the duties of Māori teacher, undertaking arduous journeys to preach at Pātea, Tarawera, Tāngōio, Te Hāwera, Manawatū and the scattered villages of Wairarapa. Kawepō wished to marry Hārata Keokeo (referred to by Colenso as Charlotte Tawhi), but she ran off with Alexander Alexander, the European trader at Onepoto. Kawepō married Māora of Ngāti Hinemanu; they had a son, who died at the age of six.
In his missionary journeys Kawepō was also successful in persuading many of his people to return to Heretaunga; some settled with him at Pokonao, upriver from the mission station at Waitangi, south of Ahuriri (Napier). During 1849 his relationship with Colenso had deteriorated, as he became impatient with the missionary's dictatorial manner and methods. The final break came in January 1850, when Kawepō threatened to drive Colenso from the North Island.
When Donald McLean arrived late in 1850 to purchase land in Hawke's Bay for the Crown, Kawepō was eager to sell, but later in the 1850s he began to oppose Tāreha, Kurupō Te Moananui and above all Te Hāpuku, who were selling huge blocks of land. He succeeded in converting Tāreha and Te Moananui to his way of thinking, no very difficult task, for they too were angered by Te Hāpuku's assumption of authority in the matter of land selling and his tendency to include their lands in his sales. Kawepō's stand resulted in his being regarded as the protector of Hawke's Bay lands from Maraekākaho to the ranges, and across to the borders of Murimotu, in the centre of the North Island. Te Hāpuku's attempt to encroach on the bush known as Te Pakiaka was the final straw and war broke out in August 1857 between Te Hāpuku's supporters and a Ngāti Kahungunu confederation led by Te Moananui and Tāreha. Kawepō was one of the war leaders, and was slightly wounded on the first day of fighting. Peace was made in 1858.
When Te Moananui declared his support for the Māori King in 1859, Kawepō was not in agreement, although he declared his support for the rūnanga system of Māori self-government. Kawepō was held in great respect by most European administrators, and his opinions concerning national events were often quoted. His opinions were based on fact-finding; and his judgements were fair to both sides. His open-mindedness, honesty and intelligence were often praised, but he was no government sycophant. He sympathised deeply with Wiremu Kīngi Te Rangitāke of Te Āti Awa, and his inclination to support the King movement in the early 1860s sprang from his fear that Māori title to land would not be respected by the governor.
Kawepō was a consistent enemy of Pai Mārire activity in Hawke's Bay. To some extent this was a reflection of his opposition to Te Hāpuku, who encouraged Hauhau to settle in his pā to strengthen himself against his rivals. In October 1866, when armed Hauhau had occupied Ōmarunui, seven miles from Napier, Kawepō and Karaitiana Takamoana joined Lieutenant Colonel G. S. Whitmore's advance to drive them out. Kawepō greatly distinguished himself in the ensuing battle.
Kawepō took a prominent part in the campaign against Te Kooti from 1868 to 1870. He was one of the leaders of the Hawke's Bay contingent which went to Poverty Bay when Te Kooti attacked in November 1868. At the engagement with Te Kooti's forces at Mākāretu, he narrowly escaped death when heavy fire drove back his men. In June 1869 he was unwilling to take a force to the Taupō area, tired of chasing on short rations through soaking wet bush after an elusive Te Kooti, a course which he had advised against as pointless. However, by September 1869 he and Hēnare Tōmoana had led a strong contingent against Te Kooti in the Tokaanu area.
In October, at the taking of Te Pōrere pā, Kawepō was clubbed from behind by a young Taupō woman, the widow of Paurini, a chief who had been killed during the attack on the pā. In revenge for her husband's death she gouged out Kawepō's right eye. Kawepō held on to her until help arrived, and would not allow his people to harm her; he considered that she had acted correctly, and later married her. He was eventually awarded a pension of £100 as compensation for his injury and in recognition of his services to the Crown. His part in the military action cost him dearly, and he was forced to sell land to cover the cost of the campaign.
In the 1860s and 1870s Kawepō had leased and sold land, but unlike many of his contemporaries, he did not spend extravagantly, or go into debt. He was bitterly disappointed by the ineffectiveness of the 1873 commission of inquiry into Hawke's Bay land alienation, and joined in the agitation for a new commission with greater powers, to inquire into and settle all land complaints. Initially he had been opposed to the movement to repudiate all land agreements, begun in Hawke's Bay in 1871–72, but in May 1873 he gave the Repudiationists some financial support. However by 1874 he had become estranged from the Repudiation movement. In September and October 1873 Kawepō attended the parliamentary session in Wellington, coming back convinced that all the laws passed were aimed at getting hold of Māori lands, and that the cost of surveys would be deducted from the purchase price.
Rēnata Kawepō's interests were broad. He was involved in negotiations with Whanganui people over the disputed borders of the Murimotu area. He distributed sheep to his people, providing the base for a new industry. He erected flour mills, contributed to the building of roads and bridges, and collected rents and distributed them fairly. He played an important role in the setting up of the Ōwhāoko Māori School reserve endowment of 60,000 acres, and gave money and support to the school at Ōmāhu, his principal settlement, established in 1867. He took a close interest in the administration of the Te Aute Trust and the school established there, and demanded that the children be taught academic subjects and do less manual labour. In 1877 his name headed a petition to the government asking for schools to be established so that Māori children might be taught English, to put them on an equal footing with Europeans in the future. He also supported the church financially and established the Church of St John at Ōmāhu.
By 1880, after the deaths of Tāreha, Karaitiana and Te Hāpuku, Kawepō was considered the senior leader of Hawke's Bay Māori. In 1883 he welcomed Tāwhiao, the second Māori King, on his visit to Hawke's Bay and received him with lavish hospitality.
Rēnata Kawepō died on 14 April 1888 at Ōmāhu. His tangi was attended by some 6,000 people. He received a military funeral and was buried in the cemetery of his church. He was said to be 80 years of age.