The present study investigated whether personality hardiness predicts peer ratings of leadership style in Navy officer cadets. Cadets (n = 71) completed the Dispositional Resiliency (hardiness) Scale, and later rated their peers using the Multifactor Leadership Questionnaire (full range of leadership model). Results show the hardy–commitment facet predicted peer ratings of all leadership styles covered in the model, both before and after and intensive military exercise. The challenge facet was a positive predictor of transformational and transactional leadership and was negatively related to passive-avoidant leadership. Transformational leadership predicted leader performance, as indexed by military development grades; and a partial mediation effect was found for hardiness on the relation between transformational leadership and leader performance.