The Building Healthy Children (BHC) home-visiting preventive intervention was designed to provide concrete support and evidence-based intervention to young mothers and their infants who were at heightened risk for child maltreatment and poor developmental outcomes. This paper presents two studies examining the short- and long-term effectiveness of this program at promoting positive parenting and maternal mental health, while preventing child maltreatment and harsh parenting. It also examines the intervention's sustained effect on child symptomatology and self-regulation. At baseline, young mothers and their infants were randomly assigned to receive BHC or Enhanced Community Standard. Families were assessed longitudinally across four time points. Data were also collected from the child's teacher at follow-up. Mothers who received BHC evidenced significant reductions in depressive symptoms at mid-intervention, which was associated with improvements in parenting self-efficacy and stress as well as decreased child internalizing and externalizing symptoms at postintervention. The follow-up study found that BHC mothers exhibited less harsh and inconsistent parenting, and marginally less psychological aggression. BHC children also exhibited less externalizing behavior and self-regulatory difficulties across parent and teacher report. Following the impactful legacy of Dr. Edward Zigler, these findings underline the importance of early, evidence-based prevention to promote well-being in high-risk children and families.