Her father, Malcolm Robert Graham, was a physician and her mother Florence (née Bloy) was a nurse.
When Graham was one, the family moved to Sandwich, Ontario (now part of Windsor), where her father became the superintendent of the sanatorium.
Zion was urged by his new wife and also his editor, Ursula Nordstrom of Harper and Brothers, to write children's books.
He remembers that it was Graham’s sketch of children gathering apples in an orchard, done several years earlier in Canada, that inspired his first book, All Falling Down (1951).
Graham remarried in 1972 to a merchant-ship officer, Oliver W. Holmes, Jr.[4] She lived in retirement in Cambridge, Massachusetts.