Examined correlates of positive father caregiving and harsh control among 721 (350 girls) four-year-old children through analysis of NICHD Study of Early Child Care data and 7050 (3450 girls) four-year-old children through analysis of Early Childhood Longitudinal Study-Birth Cohort data. Findings from both samples suggest that, for both boys and girls, father positive care is associated with lower levels of impulsivity and higher ratings of inhibitory control. For girls, father positive care is associated with lower ratings of aggression. For boys, these findings suggest self-regulation moderates associations between father positive care and aggression. Some support was obtained for models of both moderation and mediation in the prediction of children's peer-based behaviour.