Born in Oregon and raised in Montana, Mary Kirkwood earned a bachelor of arts degree from the University of Montana and a master of fine arts degree from the University of Oregon. She also completed graduate work at the Royal Art School at Stockholm, Sweden and the College of Art Study Abroad in Paris.

In 1930 she joined the faculty at the University of Idaho as a professor of painting, composition, and history of painting. Kirkwood was described as an inspirational teacher and encouraged her former students to strive for greater artistic development.

"Painting the human figure is to me more than satisfying," Kirkwood wrote in an artist's statement. "After some confusion in earlier years about keeping up with the changing movements, I came to realize that painting was more than a body of knowledge or even a way of thinking; it was a way of feeling, and feeling could not be altered casually by events outside of one's own nature or the vital experience that had roots in one's youth."