Hira Te Popo was the only son of Tāne Whirinaki. No record of his mother's name has been found. He was born into Te Whakatōhea of Ōpōtiki, a tribe which was trying to recover from the devastating raids of Ngāpuhi and Ngāti Maru in the 1820s. Little is known of his early life. His wife's name was Tire; they had a son named Merihika, and a daughter named Matu.
By 1860 Hira Te Popo's hapū, Ngāti Ira, had become wealthy traders and farmers. A flour mill was built on their land in 1861. The Hira, a cutter registered in Hira Te Popo's name and owned by Ngāti Ira, was used to transport their produce to the Auckland market. Land sales and the confrontations that were taking place between Māori and the government would have been discussed with people from other North Island tribes trading goods in Auckland. Hira Te Popo became a firm supporter of the King movement.
Early in 1864 the Reverend C. S. Völkner, Anglican missionary at Ōpōtiki, reported to Governor George Grey that 700 or 800 armed Māori were assembled in the eastern Bay of Plenty. Hira Te Popo and some of Ngāti Ira were with this force, known as the Tai Rāwhiti expedition, whose object was to go to Waikato to assist in resistance against invading government forces. An attempt was made to reach Waikato via Rotorua, but Te Arawa refused permission to cross their territory. After some skirmishing around the Rotorua lakes the expedition returned and disbanded. In April 1864 they reassembled and moved up the coast to Maketū. Government troops and Te Arawa, assisted by British naval vessels, defeated them and they retreated back down the coast. During the fighting a number of Ngāti Ira were killed, and Hira Te Popo narrowly avoided death or capture at the final battle at Te Kaokaoroa, near Matatā.
In February 1865 Kereopa Te Rau and Patara Raukatauri arrived in Ōpōtiki as missionaries for the Pai Mārire religion, and Völkner was seized and hanged. Hira Te Popo and Ngāti Ira were opposed to Völkner's execution and took no part in it. Nevertheless, in the savage government confiscations of land around Ōpōtiki which followed, Ngāti Ira were to lose nearly all of their good land.
In September 1865 government troops landed at Ōpōtiki and captured the town. The troops then fortified the Anglican church, and began probing sorties into the surrounding countryside. Early in October they were moving up the cart road that ran from Ōpōtiki to the Ngāti Ira pā of Te Puia, Ōpekerau and Te Tarata. In these palisaded pā Hira Te Popo had made preparations to resist the government forces. The troops surrounded and attacked Te Tarata, on the Kiorekino plain (Waioeka flats).
The people in Te Puia pā could see that Te Tarata was in trouble and set out to help. They were observed by government cavalry, who charged, killing 20 Te Whakatōhea and wounding a number of others. During the night the defenders of Te Tarata rushed out, most of them escaping to the bush. Hira Te Popo decided to abandon all the fortified pā and with his people retreated back up the Waioeka River. During the following weeks other leaders of Te Whakatōhea came in to Ōpōtiki to surrender and sign the oath of allegiance, but for the next four years Hira Te Popo and Ngāti Ira stayed in the upper reaches of the Waioeka and Waimana rivers.
In January 1869 Te Kooti Arikirangi arrived in the Waioeka area. He converted Hira Te Popo and most of Ngāti Ira to the Ringatū faith. Ngāti Ira and Ngai Tama of Tūhoe planted gardens and built Te Kooti a substantial village in the Waioeka Gorge at Maraetahi, near Ōpōnae. In March 1870 the village was captured and destroyed by government forces. Although some of Ngāti Ira joined Te Kooti's fighting force, Hira Te Popo did not take up arms himself. By June 1870 most of Ngāti Ira were already in Ōpōtiki, and Hira Te Popo and the last of his men came in and submitted to the government.
Government officials were pleased at Hira Te Popo's surrender. The resident magistrate at Ōpōtiki, W. G. Mair, reported that his defection would prove a severe blow to Te Kooti's cause. 'At the same time', he added, 'his accession to our party will be a great gain, as he is a man of considerable ability, and of good character.' On more than one occasion Hira Te Popo warned the government about Te Kooti's planned raids.
Hira Te Popo immediately applied to plant crops on some of the reserves at Ōpōtiki, and Ngāti Ira soon had considerable areas under cultivation. Hira's cultivated land was said to be the most productive in Ōpōtiki. He rebuilt a village and a large meeting house at Ōpekerau. Hira Te Popo wanted Ngāti Ira children to be educated and started a school at the village; a government school did not open until 1884, with 30 pupils. Active in local affairs, Hira was highly regarded by the local European settlers. In 1887 he was elected native assessor for the Native Licensing District of Waioeka. In 1889 he became ill in Auckland and returned to Waioeka where he died early in October.