Callous-unemotional (CU) behaviors increase children’s risk for subsequent antisocial behavior. This risk process may begin in early childhood with reciprocal pathways between CU behaviors and harsh parenting. In a sample of 561 linked triads of biological mothers, adoptive parents, and adopted children, the present study examined bidirectional links between CU behaviors and harsh parenting across three time points from 18 to 54 months and investigated moderation by inherited risk for psychopathic traits. Findings support reciprocal associations between harsh parenting and CU behaviors during early childhood, especially during the transition from toddlerhood (27 months) to preschool (54 months). Moreover, inherited risk moderated these associations such that links between harsh parenting and CU behaviors were stronger among children at higher inherited risk for psychopathic traits. The findings illustrate the dynamic interplay between parenting, CU behaviors, and heritable risk.