This multi-cohort study delineates developmental trajectories of psychopathic features across childhood and adolescence (ages 7–16) and investigates associations with adult outcomes (ages~23–34). Although most youth demonstrated consistently low levels of psychopathic features, approximately 10%−15% followed a chronically high trajectory. A similar number (~14%) displayed initially high levels that decreased over time, while others (~10%−20%) followed an increasing pattern. Boys in the chronically high trajectory exhibited the most deleterious adult outcomes and some evidence suggested that youth in the decreasing subgroup experienced fewer maladaptive outcomes than those in the increasing and high groups. Findings revealed substantial malleability in the developmental course of psychopathic features and suggest that unique pathways may exert considerable influence on future engagement in antisocial and criminal behaviors.