Here, we investigate how facial trustworthiness—a socially influential appearance variable—interrelates with antisocial behavior across adolescence and middle adulthood. Specifically, adolescents who look untrustworthy may be treated with suspicion, leading to antisocial behavior through expectancy effects. Alternatively, early antisocial behaviors may promote an untrustworthy appearance over time (Dorian Gray effect). We tested these expectancy and Dorian Gray effects in a longitudinal study that followed 206 at-risk boys (90% White) from ages 13–38 years. Parallel process piecewise growth models indicated that facial trustworthiness (assessed from photographs taken prospectively) declined during adolescence and then stabilized in adulthood. Consistent with expectancy effects, initial levels of facial trustworthiness were negatively related to increases in antisocial behavior during adolescence and also during adulthood. Additionally, higher initial levels of antisocial behavior predicted relative decreases in facial trustworthiness across adolescence. Adolescent boys’ facial appearance may therefore both encourage and reflect antisocial behavior over time.