Tāmati Ngākaho was of Te Whānau-a-Rāhui of Ngāti Porou, from Rākaihoea at Kākāriki, near Waiomatatini on the East Coast. His parents were Hāmure and Huirōhutu (Huirotu). Few facts about his life have been recorded, but he is celebrated as a leading exponent of the style of carving that had been founded by Iwirākau in the Waiapu–Te Araroa area in the sixteenth century. Carving was a chiefly occupation, and Ngākaho must therefore have been a man of rank.
In 1874 Tāmati Ngākaho worked on the construction of a Māori house at the Canterbury Museum in Christchurch with another Ngāti Porou carver, Hone Tahu (Taahu). Tahu had designed the house in the 1860s, and had named it Hau-te-ana-nui-o-Tangaroa (the sacred great cave of Tangaroa). It had originally been intended as a residence for Hēnare Pōtae at Tokomaru Bay, but war had prevented its construction and the surviving timbers were acquired for the museum by Samuel Locke for £290. Tahu and Ngākaho intended to build the house entirely in traditional style, but this plan was abandoned due to the expense of the project. The completed carvings were attached to a European frame on concrete foundations. The carvings were of tōtara, painted in red ochre. The scroll work on the rafters, in the pattern called mango-pare, was painted using white, black, red, green and blue prepared in the traditional way. The two carvers also gave information on their art to Julius Haast, the museum's director.
The major work for which Tāmati Ngākaho is remembered is Porourangi, the meeting house at Waiomatatini. The timber for the house had been cut in 1865, for a house whose construction had to be abandoned, again because of fighting in Waiapu. The carvings for Porourangi are by Tāmati Ngākaho and Kihirini Te Aotapunui. The carvers may have been closely related, and both were from Rākaihoea. It is known that Kihirini had been at the same carving school as Raharuhi Rukupō of Tūranga (Gisborne). Kihirini had carved the ridge-pole in three sections before the war. They had been floated down the Mangaoporo and Waiapu rivers to Rangitukia, intended for shipment to Hawke's Bay for Te Hāpuku; but when Rāpata Wahawaha moved from Waipiro Bay to Waiomatatini in 1875 or 1876, he secured the timbers to build a house for Ngāti Porou. Tāmati Ngākaho worked with an adze on the slabs for Porourangi. The relief of the figures was built up and made smooth, ready for detailed ornamentation. The finer carving was done afterwards by Ngākaho, who carved most of the interior except for two carved uprights and the ridge-pole over the porch, which were carved by Kihirini. Kihirini is said to have died before the house was completed. An observer said that Ngākaho carved with an ordinary table knife that had been ground to a point. Ngākaho also supervised the construction of the building. The house was opened in 1888.
Ngākaho was presumably a mature man by the time he became prominent as a carver, and may have died about 1904. His brother, Te Karaka, was also a carver. Tāmati Ngākaho held an interest in a number of land blocks including Kōrakonui, Wharau No 2 and Whakarei No 1. His wife was Arapera Tamatama; they had at least three children.