Hostility is a risk factor for cardiovascular events. When challenged, individuals high on hostility exhibit a hyperreactive psychophysiological response to stressors, thereby increasing risk for developing cardiovascular disease. However, low resting heart rate (HR) is associated with physical aggression and hostility in children, adolescents, and adults. Based on a community sample of 296 men (mean age = 32.0), we (a) address whether aggression/hostility relates to physical health through relationships with cardiovascular levels at rest and in response to stressors, and (b) determine how relations between aggression and health are altered by including psychophysiological indices in statistical models. The Cook‐Medley cynical/hostile attitudes and the Buss‐Perry physical aggression and hostility measures assessed aggression. Health was assessed as systolic blood pressure (SBP), report of medical conditions, and a metabolic composite. Reactivity to stressors was assessed with HR, SBP, and diastolic blood pressure. Aggression was negatively related to both resting HR and reactivity. High resting HR and reactivity were, however, positively related to poor health. Thus, the relationship between aggression and HR and reactivity suppressed an overall relationship between high aggression/hostility and poor health. In the presence of covariates for socioeconomic status, race, health behaviors, and medications, the relationship between aggression and health was significantly strengthened when HR level and reactivity were included in models. In sum, at early midlife, low HR among aggressive and hostile individuals is related to less health risk. Aggression and hostility have a deleterious influence on health, but primarily among individuals with higher HR and possibly greater cardiovascular reactivity.