After leading his Te Atiawa tribe from its native North Island province of Taranaki to a place near Wellington in 1833, Kingi was converted to Christianity by the English missionary Octavius Hadfield and was initially friendly toward Europeans. He supported Hadfield against the aggressive Maori chiefs Te Rauparaha and Te Rangihaeata. In 1847, however, Kingi refused to abandon his land claims in the Waitara district of Taranaki province to the governor, Sir George Grey, and led his people back to settle on their ancestral lands. War broke out in Taranaki in 1860, when Governor Gore Browne purchased the tribal Waitara land block over Kingi's objection and in ignorance of Maori land customs. Kingi aligned himself with Potatau I (Te Wherowhero), leader of the militant Maori King Movement (a loose federation of tribes opposed to further land sales to colonists), and, in the course of the fighting, withdrew to the Waikato, the movement's heartland.

Kingi led his people in the Waikato War (1863–64) with colonial troops and did not submit to colonial authority until 1872. The legitimacy of Kingi's Waitara land claims was recognized in 1863, and in 1926 the New Zealand government awarded the Taranaki tribes an annual grant of £5,000 in compensation for their confiscated lands.