The identification and understanding of alterable influences on well-being are at the nexus of developmental science and social policy. These influences span the life course but child, family, and school experiences in the first two decades are particularly instrumental to health and well-being. To investigate some of these influences, we report data from the Chicago Longitudinal Study. The study investigates the life course development of 1,539 children (93% African American and 7% Hispanic) who were born in 1979-1980, grew up in the highest-poverty neighborhoods in Chicago, and attended early childhood intervention programs beginning in preschool. The goals of the study are to determine the effects of participation in the Child-Parent Center Program, document patterns of child and family well-being over time, and identify child, family, school, and community factors that can promote children’s well being. We describe major intervention findings and summarize the contributions of a variety of personal, family, and school experiences in promoting multiple domains of well-being.