Ānaha Kēpa Te Rāhui, also known as Ānaha Mātao, is thought to have been born in the early 1820s, at Te Koutu pā on Lake Okataina. He was descended from Te Rangi-takaroro by his first wife, Rangipare. His father was Te Rāhui, a leading man of Ngāti Tarāwhai of Te Arawa, and a well-known canoe builder. His mother was Rangihōnea, who lived before her marriage with Ngāti Pikiao at Rotoiti. Ānaha grew up around Lake Okataina, where he and his elder brother, Wiremu Kīngi Te Ohu, learned their skills from their father.
During Ānaha's youth Ngāti Tarāwhai, led by Te Iwimōkai, were establishing themselves at Ruatō, on the southern side of Rotoiti. Ānaha often stayed there with his Ngāti Pikiao relatives. In 1835 the missionary Thomas Chapman began to work in the Rotorua district, and soon Ānaha and his whole family became involved in the new religion. By 1838 Ānaha was living at Tāhunapō, an outpost of Chapman's Rotorua mission station, with Houa Te Hauiti and other Ngāti Tarāwhai Christian teachers. With the other mission students he retreated to Te Koutu when a Ngāti Pikiao force arrived to avenge the killing of their kinsman, Te Wharepurupuru, by Tangatauia of Ngāti Tarāwhai; Ngāti Pikiao withdrew after firing a few shots in the air.
Ānaha spent the next few years living about Lake Okataina, cultivating the family gardens, learning skills from his father and other experts, and building canoes for a number of clients. The first canoe on which he worked was Te Arapaenga. In 1847 he and his parents were among Ngāti Tarāwhai who moved their homes and gardens to be near Chapman's mission station at Te Ngae. While his brother, Te Ohu, became a Christian teacher at Okataina, Ānaha was gradually assuming the leadership of Ngāti Tarāwhai. He married Wahia, the daughter of Te Iwimōkai, and their children were born at Rotorua, Okataina and Rotoiti.
In 1861 or early 1862 Ānaha was appointed the assessor at Okataina under Governor George Grey's new runanga system. He had to give up his cultivations and spend more time on tribal business at Okataina and Ruatō. The Ngāti Pikiao leader Te Waata Taranui asked Ānaha to reside at Ruatō to help him deal with government business. By 1864 Ānaha was the acknowledged leader of Ngāti Tarāwhai; during the wars of the following years he led Ngāti Tarāwhai through many campaigns involving Te Arawa contingents on the government side. He became a close friend and associate of Captain Gilbert Mair.
When the district was settling down after the wars, Ānaha lived mainly at Ruatō, and also at Okataina and Rotorua. Children in his family attended the Rotoiti school, set up at Tāheke in 1871. Although he continued to carve, more of his energy was devoted to Native Land Court hearings, both as an assessor and as a claimant. He developed special skill in the courtroom and his evidence was always notable for its clarity and conciseness; he was instrumental in establishing the boundaries of the ancient Ngāti Tarāwhai lands at Okataina, which were made a scenic reserve. In the years after the wars many Ngāti Tarāwhai became followers of the Ringatū faith, and Ānaha must have been in close contact and sympathy with these beliefs.
At this time Ngāti Tarāwhai carvers were busy building new, large, carved meeting houses for Ngāti Pikiao and others, and Ānaha participated in this activity. Meeting houses carved for Māori patrons with which he is especially associated are Rangitihi in 1867–71 and Tokopikowhakahau in 1877. Rangitihi stood at Tāheke, on the northern shore of Rotoiti. Most of its carvings are now in the Auckland War Memorial Museum, while one panel is in St Petersburg, Russia. Along with Tene Waitere and Neke Kapua, he was employed in 1897 and again in 1904 by Charles Nelson of the Geyser Hotel in Whakarewarewa to complete the carvings for Rauru and Nuku-Te-apiapi. These were houses which Nelson erected purely for entertaining tourists. Around the turn of the century, Ānaha was involved in the production of smaller carvings for sale to Europeans. He became an innovator in designing small bowls, ornate, carved jewellery chests, tobacco pipes, tinder boxes and replicas of traditional artefacts. The museums in Auckland and Wellington contracted him to supply items for their Māori displays.
Ānaha Te Rāhui was a master of traditional learning, and was responsible for setting down a great body of tribal history in the course of his testimony at Native Land Court hearings. At the same time he acquired competence in European ways and skills through his missionary education and his experience in court hearings. The way in which he gave evidence suggests something of his character. He made his points in logical order, carefully, thoroughly and methodically. He made no extravagant claims and dealt calmly with each objection. Photographs of him, which are numerous because of his close connections with Europeans, show a distinguished-looking man with a moustache and beard.
Ānaha died at Ōhinemutu on 30 September 1913 and was buried at Ruatō. The last of the Ngāti Tarāwhai canoe builders, he was thought to be over 90 years of age. He was very much a man of his people, a great leader, an artist and a capable man of affairs.