We assess life-course changes in how cognitive and noncognitive skills mediate the effect of parental SES on children's academic achievement using data from the Early Childhood Longitudinal Study-Kindergarten Cohort. Our results show: (1) the direct effect of parental SES declines while the mediating effect of skills increases over time; (2) cognitive and non-cognitive skills differ in their temporal sensitivities to parental origin; and (3) in contrast to the effect of cognitive skills, the mediating effect of non-cognitive skills increases over time because non-cognitive skills are more sensitive to changes in parental SES. Our results offer insights into the dynamic role skill formation play in status attainment.