Dispositional characteristics are associated with important life outcomes across the lifespan, often predicting outcomes decades in advance. Evidence has accrued to demonstrate that personality characteristics measured during childhood and adolescence show unique effects on later life outcomes above and beyond adult personality. Currently it is unclear why personality produces unique effects at different life stages, given the modest consistency of personality across the lifespan. The current article sets forth potential explanations for why these unique predictive effects may occur, charting multiple pathways that link childhood personality to later outcomes that differ from how adult personality influences the same products. We conclude by providing directions for future longitudinal investigations into when, why, and how assessments of childhood personality can help advance our understanding of lifespan development.