Although the association between immature defensive styles to protect oneself from conflict in emotional context and reactive aggression (RA) has been shown recently among nonclinical individuals, the factors that may explain this relationship remain poorly understood. One putative factor is negative urgency as impulsive individuals tend to react aggressively in emotional contexts. This study aims to verify whether the relationship between image distorting defensive style and RA is moderated and not mediated by negative urgency of trait impulsivity. Nonclinical participants completed the Defensive Style Questionnaire, the UPPS Impulsivity Behavior Scale, and the Reactive-Proactive Aggression Questionnaire. Contrary to what was expected, the results showed that the relationship between image distortion and RA was entirely mediated but not moderated by the effect of negative urgency. These results suggest that when individuals get in a defensive state leading to a distortion of the image of themselves and others, they become more emotionally impulsive, leading to RA.