In 2016, the City of Chicago embarked on a bold initiative to expand the evidence-based Becoming a Man (BAM) group mentoring model to serve thousands of young men. To reach this ambitious goal, the City’s Department of Family and Support Services (DFSS) quickly expanded existing contracts for BAM and 11 other mentoring programs. It then undertook an innovative Request for Proposal (RFP) process – which elevated best practices identified in a rigorous evaluation of the BAM program – and awarded 45 community-based organizations new contracts to grow their mentoring programs and infuse them with evidence-based practices. DFSS increased the number of youth receiving high-quality mentoring from 800 to more than 7,000 in less than three years. It also built a data-driven, equitable service delivery model that harnessed the collective strength of existing community-based organizations. Philanthropic support, which helped the program expand, has now been largely replaced by City funding (more than $50 million since 2017) to ensure that Chicago youth continue to benefit from these services into the future.