This research aimed to categorize perpetrator’s aggression as reactive or proactive regarding intimate partner violence and explore the relationship with relevant variables. Victim statements in police reports of 60 predominantly Hispanic male adult perpetrators on probation in South Texas were rated, categorizing statements as reactive or proactive. It was hypothesized that more men would display reactive aggression and it would be associated with severe violence, emotion regulation difficulties, state anger, and impulsivity. The study further suggested that emotion regulation, state anger, and impulsivity would moderate the relationship between severity of violence and reactive/proactive classification, and impulsivity would mediate the relationship between state anger and reactive/proactive classification. Results showed 79% of perpetrators using reactive aggression and 21% using proactive aggression. Men with reactive aggression exhibited more severe violence, emotion regulation difficulties, impulsivity, and state anger. There were no moderation effects of study variables on severity of violence and reactive/proactive classification. Impulsivity fully mediated the relationship between state anger and reactive/proactive classification. Our results support approaches that emphasize reactive aggression in intimate partner violence perpetration due to its frequency and potential recidivism effects.