Dissemination of innovations is widely considered the sine qua non for system improvement. At least two dozen states are rolling out evidence-based mental health practices targeted at children and families using trainings, consultations, webinars, and learning collaboratives to improve quality and outcomes. In New York State (NYS) a group of researchers, policymakers, providers, and family support specialists have worked in partnership since 2002 to redesign and evaluate the children's mental health system. Five system strategies driven by empirically based practices and organized within a state-supported infrastructure have been used in the child and family service system with more than 2,000 providers: (a) business practices, (b) use of health information technologies in quality improvement, (c) specific clinical interventions targeted at common childhood disorders, (d) parent activation, and (e) quality indicator development. The NYS system has provided a laboratory for naturalistic experiments. We describe these initiatives, key findings and challenges, lessons learned for scaling, and implications for creating evidence-based implementation policies in state systems.