She initially attended Cornell University as a graduate student, studying cognitive and perceptual psychology with Elizabeth Spelke.
She transferred a year later to the University of Pennsylvania to study philosophy under the direction of Gary Hatfield.
She received her Ph.D. in philosophy from Penn in 1994 and took her first academic job as assistant professor at Harvard University.
In 2002, she became the first woman to be tenured from a junior faculty position within Harvard's philosophy department.
Simmons' work on Descartes has been particularly influential, and she additionally serves as a jury member for the million-dollar Berggruen Prize.