After graduating from St. Thomas High School, she attended McGill University on a scholarship, and received her bachelor's degree in 1968.

In 1991, she published Labyrinth of Desire, a meditation on women and romantic obsession, and in 2006, Villa Air-Bel: World War II, Escape and a House in Marseille, which won the Canadian Jewish Books Yad Vashem Award in Holocaust History.

[5] Sullivan was appointed an Officer of the Order of Canada in 2012[6] and received the Queen Elizabeth II Diamond Jubilee Medal that same year.

In 2008, she received the Lorne Pierce Medal for Major Contribution to Canadian Literature, the Royal Society of Canada.

In 2015, she won the Hilary Weston Writers' Trust Prize for Nonfiction for Stalin's Daughter, her biography of Svetlana Alliluyeva.