There is power in revisiting the underlying foundational principles of our past and looking at how they can inform our present and future functioning. This chapter looks back at the historic foundational principles of rehabilitation psychology (RP) and shows the links to current research on the psychology of well-being and explores implications for providing meaningful interventions that could improve the lives of persons with disability and chronic illness. It reviews how positive psychology (PP) approaches have been used for people with disabilities (PWD), presents an overview of the development and structure of well-being therapy (WBT), including a literature review, and then demonstrates how it could be applied to people with spinal cord injury (SCI). The chapter concludes with a discussion of the broader implications for utilizing these approaches more widely in RP as well as a cautionary note.