Ihaka Whaanga, born perhaps late in the eighteenth century, was the son of Te Ratau of Ngati Rakai-paaka and Ngati Kahungunu. Te Ratau was killed and eaten in a conflict with Te Whakatohea at Ohiwa and his own relative Matenga Tukareaho of Nuhaka. Whaanga was the youngest and only survivor of six sons of Te Ratau and Kainga.
Little is known of Whaanga's involvement in Nga Puhi campaigns in Heretaunga (Hawke's Bay) in the early 1820s. About this time a European known to Whaanga as Hare, J. W. Harris, first arrived in the Mahia area in his vessel, Fanny. He visited the district regularly in the 1820s, and traded muskets and powder for flax fibre. Whaanga became the patron of the whaling station set up at Mahia in 1837, and by 1851 he had at least 140 Europeans and 280 Maori whalers living under his protection. Whaanga was known for his kindness and generosity to Maori and Pakeha alike.
When Donald McLean, then a government land agent, first encountered him in 1851, Whaanga was known as Ihaka (Isaac), and was presumably already a Christian. McLean described him as 'principal Chief of te Mahias Pa'. Whaanga and other Mahia chiefs offered to sell a large block of land to the government, but at that time McLean did not accept.
Always positive in his attitude to European trading and settlement, Whaanga became a supporter of the European administration. On 1 January 1863 he was appointed an assessor under the Native Circuit Courts Act 1858 at a salary of £30 per annum, a position with responsibility for law enforcement and some of the duties of a local magistrate. As alarm at the rumours of growing Maori support for the King movement spread among Hawke's Bay settlers in 1863, Whaanga was among those who reassured Pakeha by speaking strongly in support of peace.
In 1864 the land purchase officer Samuel Locke began negotiating with Whaanga and other chiefs to purchase land in the Mahia and Nuhaka areas. Although initially hesitant, especially regarding the extent of territory sought by the Crown agent, Whaanga consented to the sale of the 16,000 acre Mahia block. One motive for the sale was a desire to demonstrate support for the government: in this area those willing to sell land were regarded as supporters of the Queen, and those opposed to land selling turned to the King and Pai Marire movements. East Coast Maori leaders, including Wi Pere and others of Rongowhakaata, disputed Whaanga's right to sell. A meeting was held at Waiwhara, on the Mahia peninsula, at which Whaanga's opponents sought to collect and return the money paid for the Mahia block, and to obtain agreement to block any further sales. Whaanga and Paora Te Apatu told them the land had gone to the Crown. Believing that Rongowhakaata were about to go to war over the issue, Whaanga asked Locke to request arms from the government to resist them.
Early in 1865 Pai Marire emissaries from Waikato were preaching in Hawke's Bay. Locke planned to confront Te Hapuku of Ngati Te Whatu-i-apiti, their protector, with Whaanga at his side. At Wairoa there were many converts, but Whaanga had remained firm in his opposition to the new religion. The chiefs who supported the government met on 24 March; they felt themselves to be a threatened minority, unsure even of how many of their own relatives supported Pai Marire. In the same month Whaanga was sent 60 Enfield rifles and a carbine. In April he and Paora Rerepu confronted King movement and Pai Marire sympathisers from Napier at a meeting at Matiti, silencing them with scorn and reproaches. In May his mana was increased and further support ensured when McLean, now Hawke's Bay provincial superintendent, visited his pa.
In November 1865 Whaanga called a meeting at Mahia of all Maori of the peninsula and the Wairoa coast as far as Nuhaka. His aim was to discover the extent of commitment to Pai Marire, and to organise the rest in the event of any hostile invasion of the district. The oath of allegiance was administered, and was taken by many waverers. After the meeting Whaanga, Locke and 80 armed supporters travelled to Whakaki, on the coast towards Wairoa. The Pai Marire flag flying there was cut down, and the inhabitants of the pa were made to take the oath of allegiance. This performance was repeated at other pa to the south. By the time Whaanga and Locke arrived in Wairoa they had succeeded in changing the minds of a number of people.
The next month Whaanga joined Kopu Parapara and Major James Fraser, who were commanding local militia in a campaign against the Wairoa Hauhau. With the support of Rapata Wahawaha and his force of Ngati Porou they succeeded in driving the Hauhau out of a position at Omaru-hakeke. In January 1866 Kopu and Whaanga led a contingent of Ngati Kahungunu into the Waikaremoana area. Rapata Wahawaha and his force of Ngati Porou made contact with the Hauhau first, but allowed Ngati Kahungunu to take the lead because the action was to take place in their territory. Entering Te Kopane Valley, the Wairoa and Mahia forces were met by heavy firing, and were thrown into confusion. Whaanga rushed to the front, calling on his people to charge, but he was not supported. Standing almost alone, he fired his carbine, but was wounded just behind the hip. Snatching a rifle, he fired again, but took another bullet in the leg. Seeing him fall, his people rushed forward and carried him to safety. Rapata Wahawaha then secured the victory, breaking Hauhau control over inland Wairoa.
Whaanga recovered from his wounds. In return for his support of the government, his people were given gifts of food. Some time in 1865, probably from the proceeds of the sale of the Mahia block, he had purchased a sailing vessel. In August 1866 he was planning to visit Napier to hire a captain for it: his aim was to send it to the Chatham Islands to fetch some of his relatives who had gone there as whalers. Although Locke deplored his tendency to spend money in 'Town', Whaanga was not improvident. When negotiating land sales with Locke he had arranged the repurchase of about 600 acres for himself and his people at Waikokopu.
After almost nine months of peace, Pai Marire adherents from Ngati Hineuru hapu at Te Haroto and Tarawera occupied Omarunui pa, near Napier, in September 1866. Both Pakeha and Maori regarded this move as a sign of Hauhau intentions to attack Napier. Kopu Parapara, Whaanga and their forces were sent for, arriving in Napier on 11 October 1866; they marched by night with Lieutenant Colonel G. S. Whitmore's militia and took the pa at Omarunui the next day. Whaanga was one of four chiefs mentioned by Whitmore in his dispatches as having distinguished themselves in action.
Peace lasted until Te Kooti's attack on Poverty Bay in November 1868. Whaanga led his men to join the force in pursuit to Makaretu and then to Ngatapa. Although Tareha Te Moananui led many Ngati Kahungunu home after a dispute with Wahawaha, Whaanga remained, joining Rapata in his first unsupported attack on Ngatapa on 5 December 1868. In April 1869, when Te Kooti attacked the pa of Hiruharama (Jerusalem) and Te Huki, near the mouth of the Mohaka River, Whaanga led the force which attempted to raise Te Kooti's siege of Hiruharama. In August 1872 the government presented him with a sword of honour.
Quarrels over land sales continued to engage Whaanga in the late 1860s. In 1873 he did his best to counteract Henare Matua's efforts to inspire the people at Wairoa, Nuhaka and Mahia to resist further land sales, to repudiate the agreements they had made, and prevent the establishment of the telegraph line on their land without rent or compensation. In 1874, when a petition to the government incorporating all the Repudiation movement's grievances was circulated, Whaanga was one of only three local chiefs to refuse to sign.
The names of the wife or wives of Ihaka Whaanga are not recorded. His eldest son, Hirini Te Rito, married the daughter of the Mahia whaler John Smith. Ihaka Whaanga died at Mahia on 14 December 1875. He was buried on an isolated hill at the southern tip of the Mahia peninsula. On the initiative of Samuel Locke, a memorial stone was erected at Nuhaka.