Hōri Pōkai Te Ruinga signed the Treaty of Waitangi on 4 March 1840 at Karaka Bay, Tāmaki (Auckland). He was seen as one of the most important Ngāti Pāoa people to sign.
Te Ruinga’s father was Pōkai and mother was Patupatu. He married Mata Te Mahirahi; their sons were Āperahama Te Hiwinui and Hōri Rākena.
Te Ruinga had two schooners registered in his name in 1847, a period when Hauraki chiefs became involved in coastal shipping. In 1852 Te Ruinga was one of a number of Hauraki chiefs concerned about government wishes to allow prospecting for gold in Hauraki. Te Ruinga was later forced to sell land to pay his debts.
In 1853 Te Ruinga and other Ngāti Pāoa chiefs sent a letter of farewell to outgoing Governor George Grey.
In 1860 Te Ruinga was one of the chiefs invited to the conference at Kohimarama organised by Governor Thomas Gore Browne.
An obituary for Te Ruinga printed in the Aotearoa – Maori Recorder newspaper in 1861 recorded that he had died on 16 August 1860.