Tall Mountain was the daughter of a Koyukon-Athabaskan mother and Scots-Irish father and born in Nulato, Alaska. Her mother became terminally ill and Mary was adopted by a white family, who took her to the Lower 48.
Traumatized by the move and alienated from white mainstream culture, she turned to writing and her Alaskan Native background for consolation. She became a leader in the Native American literature renaissance and published in anthologies, journals and newspapers. She taught Native American studies at colleges and universities.