OBJECTIVES: This study aims to establish the effects of ACEs on multimorbidity through sleep quality and investigate whether lifestyle factors (e.g., eating habits and exercise) may influence this relationship among middle-aged and older adults. METHODS: Participants were drawn from a cross-sectional sample of community dwelling older adults ( RESULTS: Across both samples, sleep quality mediated the relationship between ACEs and chronic health conditions. Moderating effects of unhealthy eating and physical activity differed between samples. DISCUSSION: Sleep quality is an important pathway connecting ACEs and adult multimorbidity, and health behaviors may provide targets for intervention particularly in older adults.