Over the past four to five decades, multiple randomized controlled trials have verified that preventive interventions targeting key parenting skills can have far-reaching effects on improving a diverse array of child outcomes. Further, these studies have shown that parenting skills can be taught, and they are malleable. Given these advances, prevention scientists are in a position to make solid empirically based recommendations to public child service systems on using parent-mediated interventions to optimize positive outcomes for the children and families that they serve. Child welfare systems serve some of this country's most vulnerable children and families, yet they have been slow (compared to juvenile justice and mental health systems) to adopt empirically based interventions. This paper describes two child-welfare-initiated, policy-based case studies that have sought to scale-up research-based parenting skills into the routine services that caseworkers deliver to the families that they serve. In both case studies, the child welfare system leaders worked with evaluators and model developers to tailor policy, administrative, and fiscal system practices to institutionalize and sustain evidence-based practices into usual foster care services. Descriptions of the implementations, intervention models, and preliminary results are described.