Objective: To investigate whether lifetime-trauma exposure predicts all-cause mortality and whether this association is mediated or moderated by perceived control. Method: A sample of middle-aged and older adults (N = 4,961) who participated in the second wave of the Midlife in the United States Study (MIDUS) provided data. Lifetime trauma was operationalized using the reported number of potentially traumatic experiences spanning childhood through adulthood. Both the perceived constraints and mastery dimensions of perceived control were examined. Cox regression models tested main effects and interactions of lifetime trauma with mastery and constraints predicting 10-year mortality risk. Results: There was a significant main effect of lifetime trauma, b = .06, hazard ratio (HR) = 1.07, p = .032, and an interaction of trauma with mastery, b = −.08, p = .004. A greater number of traumatic experiences was associated with increased mortality risk at below-average levels of mastery, −1 SD; HR = 1.14, p < .001, but not at above-average levels, +1 SD; HR = 0.97, p = .48. This interaction persisted after further adjustment for health status, psychological, and behavioral covariates. An association of constraints with elevated mortality risk, HR = 1.33, p = .008, was attenuated in a fully adjusted model, HR = 1.06, p = .26. Conclusion: A strong sense of mastery may buffer elevated mortality risk associated with exposure to traumatic experiences. Findings extend evidence that mastery may foster resilience to the adverse health effects of traumatic stressors, whereas constraints may show stronger independent associations with health outcomes.