Garrett was born in 1923 in
Carterton, and affiliated to
Te Atiawa and
Ngati Mutunga. She grew up in a bicultural home in the
Hawke's Bay region of New Zealand, and attended Waipawa High School (now
Central Hawke's Bay College). Garrett trained as a teacher at
Wellington Teacher's College and then taught in rural schools. She joined the
Department of Māori Affairs in 1952, where she was the Māori Welfare Officer for Ikaroa District. Garrett then completed a Bachelor of Arts in psychology, and worked with the psychology services in Palmerston North and as an educational psychologist in the United Kingdom. ==Academic career==