Abstract Persistent racial/ethnic disparities in mortality in the U.S. create racial/ethnic disparities in young people’s exposure to death in their families. Such differential exposure to family member deaths in childhood and adolescence is a significant public and population health issue given the intense disruption of this family experience, the physical and mental toll of bereavement, and the cascading life course risks of adverse early life trauma. This project advances a significant interdisciplinary research agenda with an innovative conceptual model that integrates sociological, biosocial, and psychological perspectives on human development and an innovative mixed-methods design that combines quantitative analyses of an extant national sample with quantitative and qualitative analyses of a local lab-based sample. Specifically, building on the PIs’ past research illuminating the critical role of disrupted young adult transitions in lifelong sequelae of early exposure to family member deaths, this project will document the links between exposure to family member deaths in the early life course and unstable and insecure trajectories of socioeconomic attainment and family-building in young adulthood; elucidate the physiological, cognitive, psychological, and social mechanisms (e.g., emotional dysregulation, maladaptive learning, physical wear and tear, psychological scarring, counterproductive coping behaviors) underlying these life course linkages; and identify concrete sources of resilience (e.g., opportunities to achieve and connect) that allow young people facing such risks to have more stable transitions into adulthood. These aims will be pursued by applying longitudinal modeling techniques and tools for promoting causal inference to nationally representative data following adolescents’ transitions into adulthood from the National Longitudinal Study of Adolescent to Adult Health. That national component will be supplemented by a local component—its feasibility already validated by a pilot—involving new data from 480 young adults participating in a laboratory-based cognitive and affective assessments, biosignal tracking, daily diaries, surveys, and qualitative interviews. Following a sequential mixed methods explanatory design that will result in a comprehensive visual map of integrated results and insights, analyses of these diverse sources of data will iteratively inform each other to refine theoretical understanding of the issue and to identify the key mechanisms that can be targeted for intervention, critical points at which to intervene, and potential social and institutional supports for resilience leverageable for intervention. Led by senior sociologists with complementary expertise and track records of NIH-funded translational mixed-methods research, this project will produce protocols, data, and recommendations that advance theory and facilitate the use of evidence for action around a set of issues that speak to a contemporary pu...