We examined associations of proactive parenting, child verbal ability, and child effortful control within the context of a randomized prevention trial focused on enhancing parenting practices in low-income families. Participants (N = 731) were assessed annually from the age of two to five, with half randomly assigned to the Family Check-Up (FCU). Results indicated that the child's verbal ability at the age of three partially mediated the influence of proactive parenting at the age of two on children's effortful control at the age of five. More importantly, the FCU indirectly facilitated children's effortful control by sequentially improving proactive parenting and children's verbal ability. The findings are discussed with respect to taking a more integrative approach to understanding early predictors and the promotion of self-regulation in early childhood.