The complexities of defining what appears to be the relatively simple concept of resilience are widely recognized. This paper analyses the concept of resilience from a range of disciplinary perspectives and clarifies a definition in order to inform research, policy and practice. The work takes a life course approach to resilience, examining evidence derived from research across the lifespan. It incorporates the methods of systematic review, concept analysis and consultation through face-to-face meetings. The synthesis of methodological approaches enables a clear identification of the antecedents, defining attributes and consequences of resilience, validated with stakeholder partners. Through this process, resilience is defined as the process of effectively negotiating, adapting to, or managing significant sources of stress or trauma. Assets and resources within the individual, their life and environment facilitate this capacity for adaptation and ‘bouncing back’ in the face of adversity. Across the life course, the experience of resilience will vary. A large proportion of resilience research is routed within the discipline of developmental psychology, and has mainly been developed with children and adolescents. A major contribution to resilience research could be made through more multi-disciplinary studies that examine the dynamics of resilience across the lifespan, its role in healthy ageing and in managing loss, such as changes in cognitive functioning.