Te Kumeroa Ngoingoi Ngāwai was of Ngāti Porou and Ngāti Koi (Hauraki) descent. A native speaker of Māori, she quickly became bilingual.
She was a leader of Te Hokowhitu-a-Tū Concert Party, which in the early 1940s travelled around the country raising funds for the war effort. Its founder, Tuini Ngāwai, supported her development as a performer and composer. Later Ngoi Pēwhairangi would write the biography, Tuini: Her Life and Her Songs (1985).
She was an advisor to the National Council on Adult Education and a promoter of Māori crafts, especially weaving. With Kāterina Mataira, she was a founder of the Te Ataarangi method of teaching and learning te reo Maori.
‘E ipo’, performed by Prince Tui Teka, and ‘Poi e’, synonymous with Dalvanius Prime and the Pātea Māori Club, were famously successful compositions. She also composed ‘Whakarongo’, a waiata urging the use of, love for and promotion of te reo Māori.
Ngoi Pēwhairangi saw te reo Māori as more than a language. It was a defining point of Māori identity.