In 2003, a coalition of public, private, and not-for-profit actors in San Francisco began work to create a local city/county supplement to the federal Earned Income Tax Credit. In addition to putting more money in the pockets of working families living in a high-cost city, the coalition sought to use the program to boost participation by eligible recipients in the federal EITC and to help low-income families connect to financial services and asset-building opportunities. This paper tells the story of San Francisco’s Working Families Credit—now in its second year—explaining how the program worked in its first year of operation, summarizing program outcomes and outputs thus far, and describing lessons learned and best practices for those considering developing a similar program in their own local jurisdictions.