Of Māori ancestry, descended from a New Zealand tribal leader, she identified with the Ngati Kahungunu iwi.

Her father, Richard William Mahupuku, farmed sheep.

He died when she was young and her mother, Emily Sexton, married another sheep farmer, Nathaniel Grace.

[2] She is best remembered for her relationship with the writer Katherine Mansfield, who was two years older than her,[1] initially while they were both at school in Wellington and then later in London and by correspondence.

[2] Mahupuku inherited substantial land and despite her lawyer embezzling some of her funds she was a rich woman.