Cathy Breen holds a Bachelor of Arts in History and Political Science from Tufts University and a Master of Education from the University of Illinois at Chicago. She began her career as a middle school teacher and has since held various leadership roles in community organizations. Breen has spent years in local governance, including serving on the Park District Board in Oak Park, Illinois, and the Falmouth Town Council, where she served as Chairwoman. She has also been active on the boards of the Community Counseling Center and Spurwink since 2013. Breen completed the Institute for Civic Leadership's Collaborative Leadership Training Program, underscoring her commitment to community service and leadership.

Cathy Breen's political identity is marked by a blend of localism and forward-thinking sustainability, with an unusual emphasis on economic growth through green initiatives. Breen's approach to economic policy is highly localized, focusing on nurturing local businesses and infrastructure, while her environmental stance champions renewable energy and public transportation. This juxtaposition reveals a strategic, ideologically agile approach that balances economic development with sustainability. Breen's rhetorical style underscores community involvement, suggesting a deeply rooted belief in civic engagement as the cornerstone of effective governance.