<p>Adolescent delinquency has been widely linked to educational failure, criminal justice involvement, and adverse health outcomes. However, less is known about how delinquent behaviors during adolescence shape precarious employment in adulthood—a critical indicator of long-term socioeconomic disadvantage. This study examines how adolescent delinquency is associated with precarious employment in adulthood and investigates the extent to which educational attainment and incarceration history mediate these relationships. Using nationally representative data from the National Longitudinal Study of Adolescent to Adult Health, we analyzed a sample of 3028 siblings followed from adolescence into adulthood. To account for unobserved, time-invariant family-level confounding, we employed sibling fixed effects models, and mediating pathways were assessed using bootstrapped mediation analysis. Results show that adolescent delinquency is significantly associated with greater precarious employment in adulthood, even after adjusting for shared family background. Mediation analyses reveal that educational attainment accounts for 11% and incarceration history for 19% of the total association, jointly explaining 28% of the observed link between delinquency and precarious employment. These findings underscore the long-term consequences of adolescent delinquency for employment quality and highlight the critical role of educational and institutional mechanisms. Interventions that promote educational continuity and mitigate the labor market stigma of justice system involvement may help reduce the risk of precarious employment among delinquent youth.</p>