Exergames have evolved from recreational activities to a powerful health promotion and rehabilitation tool. This chapter provides an overview of the history and current state of the art of research on exergames. It highlights that current literature has mainly attributed the promise of exergame-based training and rehabilitation to their superiority in providing dual physical-cognitive demands with enhanced engagement and adherence compared to conventional exercise or rehabilitation modalities. However, this chapter will demonstrate that the design options that serious exergames offer provide a plethora of additional opportunities to enhance the individualized tailoring and ecological validity of interventions beyond the possibilities of conventional approaches – provided they are purposefully developed. Methodological and conceptual frameworks are presented that guide the establishment of the next generation of serious exergames and thereby consolidate the ongoing paradigm shift from entertainment-centered recreational solutions toward serious exergames that are purposefully designed, grounded in theory, and optimized interest holder involvement from the outset. Finally, an outlook is given on the expected technological advancements and how these can bring value to efforts to unlock the full potential of exergame-enhanced interventions for individuals and public health needs.