Phillips returned to teaching in 1957, when she became associate director of a teacher-training institute at Washington University. Phillips remained at St. Louis until 1962, when she joined the faculty at the University of Chicago as a professor of physics. Under her guidance the university began teaching physical science courses to non-science majors. She also made laboratory work part of its curriculum. Phillips retired as a professor emerita from the University of Chicago in 1972, but continued to teach elsewhere.