AbstractResilience is the cornerstone to mental health, and entails multiple biological and psychological mechanistic processes. However, the interplay of the psychobiological processes in shaping resilience is unclear. Here we report the results of testing whether an acute cortisol response and positive affectivity traits moderate the relationship between participants’ five-year major life stress and current psychological symptoms. The participants comprised 147 individuals (93 females and 54 males, age = 24–45 years) without clinical diagnosis. Acute stress was induced using the Trier Social Stress Task. We found that both the cortisol response to anticipatory acute stress and positive affectivity moderated the stress–symptom relationship. Specifically, a positive relationship between life stress and current symptoms was only observed at low, but not high, levels of cortisol response and positive affectivity. Moreover, the moderating effect of cortisol response was only observed at a low level of trait positive affectivity. These results unravel how the biological and emotional processes of the stress response interact to shape resilience to major life stress.