This study investigated whether child exuberance, an aspect of temperament related to emotion regulation, moderates the well-documented association between high parenting stress and increased risk for internalizing and externalizing problems during the preschool years. At 42 months of age child exuberance was observed in 256 children (47% girls) and maternal self-reports on parenting stress were obtained. At 48 months internalizing and externalizing problems were assessed through reports from both parents. Indeed, higher maternal parenting stress increased the risk for internalizing problems, and this association was more pronounced among children with high levels of exuberance. Existent emotion regulation difficulties in highly exuberant children may further heighten the risk conveyed by an unfavorable caregiving environment for developing internalizing problems.