Aggressive behavior hurts us all and is studied across psychology’s subdisciplines. Classical theories discuss the causes of aggression in the context of negative affect (e.g., frustration, pain). However, more recent research implicates positive affect as an important correlate and cause of aggression. Such aggressive pleasure likely evolved from ancient predatory tendencies that later yielded reproductive benefits, holds across reactive and proactive forms of aggression, and is used strategically as an item in many people’s emotion-regulation toolkit. Findings from psychological and neural sciences have converged to detail aggression’s hedonically pleasant qualities and the motivational and biological mechanisms through which they occur. This new approach generates novel hypotheses and might lead to effective interventions that mollify mankind’s aggressive tendencies.