This study investigated how various risk and protective factors interface with child health and well-being at the population level. Specifically, we examined the association of income, social-contextual variables, and indicators of health-related habits and activities to children's life satisfaction and perceived overall health. Child data were collected via a self-report survey, the Middle Years Development Instrument, which was administered in three demographically diverse Canadian school districts to 5026 grade 4 students (83 % of the students had complete data and were included in the analyses). Multiple regression and mediation analyses were conducted to examine the joint associations of social relationships with adults and peers, nutrition and sleep habits, and after school sports activities with children's satisfaction with life and perceived health. Results indicate that peer belonging and relationships with adults at home and school were the strongest predictors of life satisfaction. Furthermore, the (small) association between income and life satisfaction was mediated by social relationship variables. Child reports of perceived health were predicted by peer belonging, adult relationships (home, school, neighborhood), after-school team sports, and nutrition habits. The (small) association between income and health was mediated by social relationships and team sports participation. Findings are discussed in light of previous research on social determinants and socio-economic gradients of children's health and life satisfaction.