Wahanui Huatare, also known as Reihana Te Huatare, Te Reihana Whakahoehoe and Te Wahanui, was born probably in the late 1820s. He was the son of Te Ngohiteārau, also known as Te Huatare, of Ngāti Maniapoto. His mother, Tārati, belonged to Ngāti Waiora of Mōkau and came from the Piopio area. Wahanui was raised in the upper Waipā valley. He could trace his descent to Raka, Hotunui and Tūrongo. He was the elder brother of Te Wiwini, and had a half-brother, Kaahu Huatare. Te Wiwini Huatare was to become a tohunga matakite of importance. Wahanui's wife was Te Wairingiringi from the Kāwhia area. Married according to Māori custom at an unknown date, they had no issue and so adopted children, including Tūwhāngai Hounuku and Tuaārau.
Wahanui was raised as a Christian and, according to family tradition, was asked by his elders to train as a Wesleyan Methodist minister. He studied at the Wesleyan Native Institution at Three Kings in Auckland, proving an intelligent student of great natural ability. He then returned to Te Kōpua to live among his people.
Wahanui was open to new ideas and practices, provided that they enhanced the mana of his people. In the 1850s he organised a mail service between Te Awamutu and Napier, and later set up a system of tribal administration and law enforcement which attracted the admiration of John Gorst, resident magistrate in Waikato.
In the late 1850s Wahanui was a participant in the debates attending the setting up of the King movement. As war approached, he became bitterly opposed to Pākehā institutions and government. Wahanui fought at Pukekohe and Ōrākau, and was wounded at Hairini in February 1864. It was Wahanui who, in the early 1880s, invented the King movement's device, Tarahou (cock-crow), signifying the dawn of day.
After the Waikato war the King movement had to adjust to the reality of military defeat and to the confiscation of land. Attempts by Waikato and Ngāti Maniapoto to regain sovereignty over their territories failed, and Wahanui emerged as an important leader of Ngāti Maniapoto. He was recognised as having much-needed diplomatic skills, and became a principal adviser to the Māori King, Tāwhiao. On 11 July 1881 Wahanui spoke for Tāwhiao's contingent when peace was negotiated with the government at Alexandra (Pirongia). In November 1882, in negotiations with the new minister for native affairs, John Bryce, he spoke for Tāwhiao on the question of authority over land. Fearful that the government wished to split the King movement, he declined their proposal to return confiscated land west of the Waikato and Waipā rivers, to offer Tāwhiao a house, a pension and several official positions, and to have Ngāti Maniapoto offer a portion of their territory to Tāwhiao.
Wahanui was strongly opposed to land selling by Waikato and Ngāti Maniapoto. Nevertheless, he and Rewi Maniapoto came to recognise the inevitability of the King Country being opened to Pākehā. Their strategy was to control this process while safeguarding their people's farming enterprises and maintaining as much of their mana as possible. In 1883 they finally agreed to allow a survey for a railway route to enter the King Country. Later in the year Wahanui, having demonstrated that the surveyors could not pass through the King Country without his support, assisted in rescuing the surveyor Charles Hursthouse, who had been captured by the prophet Te Mahuki and his Tekau-mā-rua movement at Te Uira. Wahanui's policy was opposed by some hapū, and matters were made worse by the cynical and secretive policies of land companies, which used Ngāti Hauā to bring land before the Native Land Court.
Together with Rewi, Wahanui signed a petition which was presented to Parliament in June 1883; they invoked the Treaty of Waitangi and the guarantee to the Māori of exclusive and undisturbed possession of their lands. They rebuked the government for legislation which contravened the treaty and argued that there was little point in roads, railways and courts if they deprived Māori of their lands. During April 1884, while Tāwhiao was in England petitioning Queen Victoria for the return of the confiscated Waikato land, the premier, Robert Stout, approached Wahanui. According to Wahanui, Stout promised that no hotel was to be built in the Ngāti Maniapoto area, no liquor was to be sold, and there would be no land courts operating in the area. In return Wahanui agreed to make land available for the railway. He received a gold medallion which allowed him and his wife free travel by rail; the right was to continue for future generations. Unfortunately, the government disregarded Stout's unwritten promises about the land, leading to a period of bad feeling on the part of Ngāti Maniapoto towards Pākehā institutions and government.
In September 1884 Wahanui declared that he would co-operate with the government over the railway on certain conditions, and he was warmly cheered when he appeared before the bar of the House of Representatives on 1 November 1884 to outline them. The conditions included the right of the King movement to manage their own affairs, the banning of liquor from Waikato–Ngāti Maniapoto territory, and the right of his people to have sole responsibility for administering their ancestral lands. Later he was offered a seat in the Legislative Council, but nothing came of it. He did, in 1886, consider standing for the Western Māori seat in the House of Representatives, but withdrew his name before polling day.
Wahanui Huatare died at Whataroa on 5 December 1897. Although he lived according to traditional Ngāti Maniapoto custom, he had remained a Christian and had acquired a deep knowledge of Scripture. His use of Scripture in public speaking added to his mana as a distinguished orator, poet and debater. Many of his sayings became proverbial. Wahanui's authority was enhanced by his physical presence: he is said to have stood six feet seven inches in height, and his ceremonial taiaha was, appropriately, very large.
Wahanui was a leading figure in Ngāti Maniapoto at a time when new policies and new methods of leadership were necessary. Although conscious of the need to preserve his own mana and that of his people, he led them cautiously towards constructive contact with the Pākehā world. Many whare on Ngāti Maniapoto marae were named by Wahanui, and remain part of his heritage. His portrait was painted by Gottfried Lindauer in 1882 and by Joseph Gaut in 1885, and there is a bust in the Te Awamutu District Museum.