Cognitive control is fundamental to successful learning and goal-directed behavior in both adults and children. Bilingual experience has been shown to facilitate cognitive control across the lifespan because of the increased cognitive demand required in managing multiple languages on a daily basis. Building on previous research that primarily compared monolinguals and bilinguals categorically, the present study examined whether variation in non-dominant language usage moderates the developmental trajectory of cognitive control in a sample of heterogeneous Spanish-English bilingual preschoolers. Using a general linear model, we found a significant interaction between the proportions of Spanish use, chronological age and performance on a cognitive control task. Results suggest that daily bilingual usage moderates preschoolers’ development in cognitive control. While bilingualism is a multidimensional experience, for developing children, daily usage is an important quantifiable indicator of bilingualism when considering cognitive control. Research and educational implications are discussed in light of these findings.