While the potential benefits of perceived overqualification are intriguing, it remains unclear why and when overqualified employees self-regulate to constructively engage with coworkers and promote positive relational outcomes. Based on optimal distinctiveness theory, we propose and test a moderated serial mediation model. This model posits that perceived overqualification enhances employees’ sense of distinctiveness, which increases their unmet need to belong. This heightened unmet need fosters interpersonal facilitation and approach-oriented relationship crafting. Additionally, servant leadership augments the effect of employees’ sense of distinctiveness, which is induced by perceived overqualification, on their unmet need to belong, making prosocial consequences more pronounced. The results of two studies (Study 1: a scenario-based experimental study with 259 employees; Study 2: a multi-wave survey study with 325 employees) support our hypotheses. These findings have both theoretical and practical implications for perceived overqualification, servant leadership, and optimal distinctiveness.