Moetara was a leader of Ngāti Korokoro at Hokianga during the period of European contact in the 1820s and 1830s. He also had connections with Te Rarawa, Te Roroa and Ngāti Whātua. He is thought to have been born in the late eighteenth century and was descended from Ngāpuhi ancestor Rāhiri and his second wife, Whakaruru. According to one account his father was Te Aitū; but local tradition states that his father was Rewha, the brother of Te Aitū. His mother, Ketekōpuru, was a descendant of Iriawa, whose people lived among Te Rarawa and Ngāti Manawa on the north side of the Hokianga Harbour. Ngāti Korokoro occupied land on the south side of Hokianga, extending from Pākanae to the head of the harbour, and south to Maunganui Bluff, including the river valleys of Waimamaku and Waipoua. Moetara's wife was Kōhau.
While Moetara was a young man his people lived under the authority of his uncle Mauwhena (or Mauhena). In this period Ngāti Korokoro were involved in wars with Te Roroa and Ngāpuhi of the Bay of Islands. Moetara is said to have placed Whiria pā, near Pākanae, under the command of Te Hukeumu when it was attacked unsuccessfully by Hongi Hika about 1812. After Hongi Hika's subsequent attack on Matarāua pā at Waihou, near present-day Panguru, Moetara's people abandoned this area, which had become tapu. When the tapu was lifted, Waihou was reoccupied exclusively by Te Rarawa. This was to become a cause of conflict between Te Rarawa and Ngāti Korokoro in the future.
In 1819 Moetara was one of the leaders of the expedition of northern tribes, under the overall leadership of Patuone, Nene and Tūwhare, which travelled down the west coast of the North Island on a journey of exploration and conquest. The war party reached Te Whanganui-a-Tara (Wellington Harbour) and penetrated Wairarapa before returning north. Moetara lost two cousins in Taranaki, and it may have been in remembrance of this that he took the additional name Motu Tongapōrutu, the name of a pā in North Taranaki. By the end of 1820 the expedition had returned to Hokianga.
Ngāti Korokoro, situated at the heads of the Hokianga Harbour, were strategically placed to profit from the European trade which developed from the 1820s, initially in kauri spars and kahikatea for building timber. The Prince Regent was the first vessel to cross the Hokianga bar safely, in April 1820; under the direction of Moetara's uncle, Mauwhena, Ngāti Korokoro daily supplied the crew with potatoes. Increasing numbers of ships followed, seeking timber, pork and potatoes, and some shore stations were established. Among the visitors was Captain John Rodolphus Kent, who married Moetara's sister, Wharo. Visitors to Pākanae remarked on the extent and order of the cultivations there. By 1828 Moetara had planted 200 acres of crops, much of which was for trade.
Moetara continued to take part in war expeditions in the mid 1820s. In 1825 he joined Hokianga forces which fought against Ngāti Whātua at Te Ika-ā-ranga-nui, near Mangawhai. Moetara and other leaders brought back many Ngāti Whātua prisoners; much later he permitted them to return to their homes. It is said that Moetara and a handful of followers were among the few to escape the massacre of the war party led by Pōmare I at the hands of Ngāti Maru and Waikato in 1826. He is said to have fled up Te Awhitū peninsula pursued by Waikato forces and escaped over the Manukau Harbour entrance by raft. By 1827, when the artist Augustus Earle visited Hokianga, Moetara was the principal leader of Ngāti Korokoro at Pākanae. His cousin Kahi, leader of Te Hikutū, also lived there with about 100 of his people.
In March 1828 war between Te Māhurehure of Waimā and Bay of Islands tribes threatened to involve the upper Hokianga people. A group of Scottish carpenters who had arrived in 1826 moved their settlement away from the seat of war to gain the protection of Moetara. Moetara ordered his people to build dwellings for his new Pākehā clients and moved his own village to be closer to them.
Two months later, in May 1828, the schooner Enterprise, which was bringing a cargo of arms and ammunition for Ngāti Korokoro, was wrecked at Whāngāpē Harbour, north of Hokianga Harbour. Immediately on hearing of this, Moetara took a party to Whāngāpē and attacked those who had already plundered the vessel. Augustus Earle speculated that it was Moetara's rage at his loss, as much as his desire to protect trade and bolster European confidence in the safety of Hokianga for commerce, that prompted this action. Moetara's eagerness to trade, however, led him to insist on his rights, through his mother Ketekōpuru, to land on the north side of the Hokianga Harbour. Already he hunted pigs there for trade.
In 1833 J. R. Clendon brought the Fortitude to Hokianga to trade for timber and moored her at the northern headland called Te Karaka. Moetara, angry that Te Hikutū and Ngāti Manawa were reaping the benefits of supplying the Fortitude, induced a man working for Clendon, named Te Haawai, to lead a party of Te Hikutū and Ngāti Manawa to plunder the vessel when it became stranded at Motukauri. This ploy permitted him to attack and force out Ngāti Manawa. With his brother Rangatira and a party of warriors he landed at Motukauri, where they were fired on by Ngāti Manawa. In the ensuing battle, afterwards known as Te Wai o te Kauri or Motukauri, Ngāti Manawa were forced to fight with spears and clubs, having left most of their guns behind at their village. At one stage Moetara was captured, but released on the orders of an enemy leader.
After this battle, which was inconclusive, Ngāti Manawa and Te Hikutū appear to have fortified themselves at the settlement of Thomas McLean, appropriating his livestock and using his planks for their pā. Moetara took his people to the sawmilling establishment of Captain William Young at Koutu. There he built a large pā enclosing the houses of the Europeans as well as the quarters of his own people. He was joined by Patuone and Nene leading a party of 300 allies. Te Rarawa, incensed at Moetara's claims to land in the north, joined his enemies. For a time a general war seemed likely, and skirmishes continued for several months. Peace was restored when the papers of the Fortitude were returned, and general agreement was reached on the respective economic spheres of the competing tribes. Mohi Tāwhai of Te Māhurehure acted as intermediary, and Moetara reluctantly agreed to restrict the hegemony of Ngāti Korokoro to the south side of the harbour.
In February 1834 Moetara was presented with a sword, cloak and letter of appreciation from Lieutenant Colonel George Arthur, the lieutenant governor of Van Diemen's Land (Tasmania), for rescuing Clendon's property. Along with these rewards a mare and foal, two of the first horses in the district, were brought as payment for some land. Moetara rode his horse, wearing his cloak and carrying his sword, at a great feast that he gave in March 1834, attended by at least 4,000 people; the occasion was the scraping of the bones of members of Ngāti Korokoro who had died at Motukauri.
Moetara was regarded by the missionaries of the Hokianga area as friendly and reliable. He was among the leaders who signed a petition to the British Crown for protection against the French in 1831, when rumours of French interest in New Zealand were causing alarm among both missionaries and Māori. On 20 March 1834 he attended a meeting at Waitangi in the Bay of Islands, called by the newly appointed British Resident, James Busby, to select a national flag. The flag was part of Busby's scheme to promote a government of confederated chiefs, and, according to one account, Moetara played an important role in its selection. Moetara also signed, in October 1835, the Declaration of the Independence of New Zealand drawn up by Busby in response to the perceived threat of Baron Charles de Thierry, who had pretensions to setting up an independent kingdom at Hokianga. Moetara, however, consistently regarded as a practical ruler by those who came into contact with him, is unlikely to have regarded the confederation of chiefs as a serious prospect.
Among Moetara's concerns in this period was the lawless behaviour of Europeans in Hokianga, often associated with drunkenness. A public meeting was held at Mangungu, on the inner reaches of the harbour, on 21 September 1835, for the purpose of prohibiting the importation and sale of spirits in the area. The meeting, chaired by the Additional British Resident, Thomas McDonnell, appointed Moetara, William Young and Henry Oakes to board and examine all vessels entering the Hokianga. This measure, however, was ineffective. Disorder continued, and in 1836 and 1837 factionalism among the European residents nearly resulted in war between Moetara, the protector of Captain William Crow, and Patuone and Nene, protectors of Crow's rebel sawyers. Later in the struggle Moetara joined with Nene and Makoare Te Taonui in threatening to expel McDonnell, one of the principal protagonists, from his establishment at Horeke.
Moetara died on 23 December 1838. Te Rarawa tradition states that he was buried at Papanui, on the north side of Hokianga Harbour. He was later exhumed and buried at Whāngāpē. Shortly before his death he had been baptised by Wesleyan missionaries, taking the name Wiremu Kīngi. He was succeeded as leader of Ngāti Korokoro by his brother Rangatira, who adopted the name Rangatira Moetara by which he signed the Treaty of Waitangi.