Stacy received a B.A. in physics and chemistry magna cum laude at LaSalle College (1977). Stacy would then go on to receive her Ph.D. from Cornell University (1981) with Professor Michell J Sienko. She was a postdoctoral fellow at Northwestern University (1981–1983) with Professor Richard van Duyne and Professor Peter Stair prior to beginning her faculty position in the college of chemistry at the University of California, Berkeley. As a junior faculty member at Berkeley, Stacy was the first recipient of the Prytanean Faculty Award, which is an unrestricted grant awarded to distinguished female faculty members at UC Berkeley.
In the area of service, and as a senior member of the faculty at the University of California, Stacy has been outspoken about her commitment to issues surrounding diversity and equity in the sciences. Stacy has served as co-investigator and principal investigator of the University of California Faculty Family-Friendly Edge, which is a Sloan Foundation research project based at UC Berkeley. In these roles and that of associate vice provost of the faculty at the University of California, Berkeley, Stacy is particularly committed to promoting "data-driven initiatives to increase equity and inclusion in faculty recruitment, advancement, and retention".
In addition to her research in the area of chemistry education at the university level, Stacy has been outspoken on the importance of exposure to chemistry research (and research in the sciences more generally) at the high school level to help promote interest in career pathways in basic research, as a pathway to improve diversity in the field, and as a strategy to enhance student learning outcomes. She has spoken on the importance of high school educators as key to these endeavors:
"I have to come to the defense of my high school colleagues. Nothing is going to change until we respect them as professionals. They have a lot to offer. They have many ideas, but no time. They are in contact with students every hour of the day. There are no longer in-service days or professional days in many states. High school teachers know what they would like to do, but they have no time to do it. Yet we treat them as if we need to go and help them. In fact, I think we have much to learn from them. Until we come to the table with our high school colleagues, acknowledging them as the high-level professionals that they are, things are not going to change."
Stacy is also the author of the book Living by Chemistry, a research-based curriculum for students at the high school level.