<p>Flourishing is increasingly conceptualized within integrative developmental frameworks that consider dynamic biopsychosocial interactions in a child’s ecology. However, there is limited research on how individual, household, and neighborhood factors interact with children’s flourishing, mental health, and school engagement. We used data from a representative sample of U.S. children (<i>n</i> = 62,789; 48.23% female) and conducted bivariate descriptive analyses and fitted a multivariate regression model for three dependent variables (flourishing, mental health, and school engagement) using the same set of independent predictors. Covariance estimates between poor mental health and flourishing (-0.10), flourishing and school engagement (0.41), and poor mental health and school engagement (-0.15) were statistically significant. Child sociometric factors, such as difficulty making friends, bullying, and their health status, were most strongly associated with flourishing, mental health, and school engagement. In contrast, neighborhood factors were only modestly associated with these three outcomes. Findings highlight both promotive and risk factors that practitioners and educators can target in interventions to strengthen child flourishing and school engagement, thereby improving outcomes.</p>