Improving community health "from the ground up" entails a comprehensive ecological approach, deep involvement of community-based entities, and addressing social determinants of population health status. Although the Centers for Disease Control and Prevention, the Office of the Surgeon General, and other authorities have called for public health to be an "inter-sector" enterprise, few models have surfaced that feature local health departments as a key part of the collaborative model for effecting community-level change. This paper presents evaluation findings and lessons learned from the Partnership for the Public's Health (PPH), a comprehensive community initiative that featured a central role for local health departments with their community partners. Funded by The California Endowment, PPH provided technical and financial resources to 39 community partnerships in 14 local health department jurisdictions in California to promote community and health department capacity building and community-level policy and systems change designed to produce long-term improvements in population health. The evaluation used multiple data sources to create progress ratings for each partnership in five goal areas related to capacity building, community health improvement programs, and policy and systems change. Overall results were generally positive; in particular, of the 37 partnerships funded continuously throughout the 5 years of the initiative, between 25% and 40% were able to make a high level of progress in each of the Initiative's five goal areas. Factors associated with partnership success were also identified by local evaluators. These results showed that health departments able to work effectively with community groups had strong, committed leaders who used creative financing mechanisms, inclusive planning processes, organizational changes, and open communication to promote collaboration with the communities they served.