Evidence indicates that patterns of biological reactivity underlie different forms of aggression, but greater precision is needed in research targeting biopsychosocial processes that underlie such differences. This study investigated how sympathetic and parasympathetic nervous system (SNS and PNS) responses to social stress were associated with multiple forms of aggression in an ethnically-diverse sample of young adult females; it further examined whether early life exposure to family conflict moderated these relationships. In the context of high levels of family conflict history, greater SNS activation during a social conflict task was associated with more direct proactive aggression and increasing RSA was associated with more direct reactive aggression. Greater SNS activation during the task was associated with more direct reactive aggression regardless of family conflict history. Our findings affirm the need to capture the contributions of multiple physiological systems simultaneously and the importance of considering family history in the study of aggression.