Minority children living in disadvantaged neighborhoods are at high risk for school dropout, delinquency, and poor health, largely due to the negative impact of poverty and stress on parenting and child development. This study evaluated a population-level, family-centered, school-based intervention designed to promote learning, behavior, and health by strengthening parenting, classroom quality, and child self-regulation during early childhood. Ten schools in urban districts serving primarily low-income Black students were randomly assigned to intervention or a "pre-kindergarten education as usual" control condition. Intervention included a family program (a 13-week behavioral parenting intervention and concurrent group for children) and professional development for early childhood teachers. The majority (88 %) of the pre-kindergarten population (N=1,050; age 4) enrolled in the trial, and nearly 60% of parents in intervention schools participated in the family program. This study evaluated intervention impact on parenting (knowledge, positive behavior support, behavior management, involvement in early learning) and child conduct problems over a 2-year period (end of kindergarten). Intent-to-treat analyses found intervention effects on parenting knowledge, positive behavior support, and teacher-rated parent involvement. For the highest-risk families, intervention also resulted in increased parent-rated involvement in early learning and decreased harsh and inconsistent behavior management. Among boys at high risk for problems based on baseline behavioral dysregulation (age 4, 23 % of sample), intervention led to lower rates of conduct problems at age 6. Family-centered intervention at the transition to school has potential to improve population health and break the cycle of disadvantage for low-income, minority families. (author abstract)