Sunderland was born in Manutuke in Poverty Bay in 1916 to Erena Te Ahuahu Maynard and Eruera Brown.

[2] She married James "Jim" Brown in 1955 at Toko Toru Tapu Church.

They had a son named Michael and she regretted that she did not teach him Maori as her own ability in two languages meant that she could operate in two different cultures.

[4] Her knowledge of Maori traditions meant that she was extensively consulted by authors writing books about their culture.

[2] The following year she was awarded a posthumous honorary doctorate by the University of Waikato.