Poitras was born in 1951 near Fort Chipewyan, Alberta, the daughter of a Cree camp cook. She was moved among Edmonton foster homes in the 1950s and was eventually raised in a white, German household. In the 1980s, Poitras, at the age of 30, studied fine arts at the University of Alberta, having already completed a degree in microbiology. At that time, she began to recover her Cree heritage and identity, through contact with the First Nations community and by experiencing Cree culture and learning its history.
Her interests in art and her native heritage grew at the same time. After moving to New York City, she began to develop her art practice and to explore aboriginal themes. Today, she has exhibited across North America and Japan. She teaches the history and philosophy of native art at the University of Alberta and serves as secretary of the Canadian Native Arts Foundation. Those who share together, stay together depicts her view of Canada's history and her hope for its future. Her work was the first new commission since 1964 for the gallery's mural program.