I don't know as much about her as I should, but our Canadian friends will soon put us right. I recall "Soldier Blue" being a hit in the early seventies. The film was important too, because it was first inkling for many people that there was something wrong with Hollywood's portrayal of Indians/Native Americans. I believe Bufy St.Marie is, at least partly Indian by descent.
I don't think she was ever seen as a "star" in the way that Joni Mitchell became one. She certainly had some success as a songwriter though. "Until It's Time For You To Go" was a hit for Elvis Presley and her brilliant, sardonic, "Universal Soldier", (associated with Donovan by a lot of peopple), was one of the defining statements of the folk/protest song movement.
You will certainly find out more about her if you do a Google search. There are many Mudcatters who have forgotten more than I ever knew about her and I am confident that they will soon turn up here to enlighten you further and correct my errors!