While the impact of violent media on aggression is well established, less is known about how individual differences influence this relationship over time. This longitudinal study addresses that gap by examining whether narcissism and sex moderated the effect of violent media consumption and reactive and proactive aggression one year later. A sample of 2,284 adolescents from Cyprus (Mage = 16, SDage = 0.89, 49.5% female) participated in this study. Hierarchical regressions, controlling for baseline levels of aggression and age, revealed distinct patterns: violent media and sex predicted reactive aggression, but narcissism did not. In contrast, violent media, sex, and narcissism all predicted proactive aggression. Notably, sex moderated the link between violent media and reactive aggression, with females showing a steeper increase than males. Both sex and narcissism moderated the violent media-proactive aggression association, with males being affected regardless of narcissism, while only highly narcissistic females showed an increase in proactive aggression. These findings show the importance of considering individual differences, such as sex and narcissism, to better understand how violent media influences different functions of aggression.