After her tenure at CLIPI, she joined the Legal Aid Foundation of Los Angeles and later served as the Executive Director of California Common Cause. Foster also taught courses on sex discrimination, federal courts, and election law as an adjunct professor at the University of San Diego School of Law. Her extensive experience in public interest law laid the foundation for her subsequent roles, including serving as a California Superior Court Judge in San Diego and later as the Director of the Office for Access to Justice at the U.S. Department of Justice.