[2] Karetai was born in Ōtākou on Otago Peninsula, the son of Te Ihutakura and Kakatuaheka, and a descendant of tribal ancestor Tahupōtiki on both sides of his whakapapa.
[1] He became a well-respected leader, liaising between his people and the newly arrived Pākehā sealers and whalers.
In 1832, Karetai was wounded in battle defending Kāi Tahu land from northern raiding parties, losing an eye.
[2] Karetai's great-granddaughter Louise Magdalene Teowaina Wallscott (1898–1999) was a notable member of the Māori Women's Welfare League.
Karetai Peak in Fiordland National Park is officially named in his honour.