The identification of factors that counter youth’s radicalization while promoting democratic activism is a timely social issue. This paper examines the association of psychological well‐being (PWB) with violent radicalism and nonviolent activism, by focusing on the mediating role of both social disconnectedness (SD) and the perceived illegitimacy of the authorities (PIoA). Two mediation structural equation models (full vs. partial) were applied to data collected from 328 Italian adolescents (14–19 years). The results showed how SD and PIoA fully mediated the link of PWB with radicalism (negatively) and activism (positively). This model was further supported when compared with an alternative one proposing PWB as a mediator between SD and PIoA. The findings are discussed in light of the existing literature and provide potential implications for practice.