Objective
To investigate the role of fathers' positive engagement as a protective factor in the development of children's behavior problems and whether this buffering effect differs by family poverty status.

Background
Children who have behavior problems at early ages are more likely to show persistent behavior problems over time. Fathers' roles in the development and persistence of child behavior problems have been less investigated than mothers' roles.

Method
Longitudinal survey data from 762 constant-resident-father families participating in the Fragile Families and Child Wellbeing Study were used. Mothers reported on children's internalizing and externalizing behavior problems when the focal child was 5 and 9 years of age, and fathers reported on their frequency of positive engagement with children at child age 5. Data were analyzed using moderated moderation regression analyses.

Results
Children living in greater family poverty at age 5 showed more internalizing and externalizing behavior problems at age 9, but greater positive engagement by fathers weakened the association between family poverty and children's later behavior problems. Moreover, fathers' positive engagement appeared to disrupt continuity in internalizing behavior problems from early to middle childhood for children in families living below the poverty level.

Conclusion
Fathers' positive engagement may serve as a protective factor for children's social–emotional development.

Implications
Emphasizing fathers' positive engagement in prevention and intervention programs designed to lower children's risk for behavior problems may have potential value.