Parental engagement in positive activities with the child may show significant variation across time, assuming a crucial influence on child development. In dual-earner families, work-family conflict can interfere with parental engagement, with negative consequences for children’s behavior. The current study examined the change trajectories of mothers’ and fathers’ engagement in early childhood, analyzing whether these trajectories are influenced by parents’ work-family conflict and whether they predict child behavioral self-control. Data from 156 four-year-old children (67 girls) from dual-earner families were collected annually for 3 consecutive years, through mothers’, fathers’, and teachers’ reports. Results from latent growth curve analysis revealed mothers’ engagement remained stable across time while fathers’ engagement had a significant increase over time. The negative association between work-family conflict and parental engagement was constant over time both for mothers and fathers. For mothers, initial levels of engagement positively predicted child behavioral self-control. As for fathers, both the initial level and positive change in engagement positively predicted child self-control. These findings emphasize the role of parental engagement in fostering child behavioral adjustment, underlining the need for considering work-family dynamics to understand changes in parental engagement.