Our work in dropout prevention and student engagement grew out of the development, implementation, and evaluation of Check & Connect. Student engagement is the foundation of theory and interventions to promote school completion. As we worked to study and understand successful school completion efforts, interest in student engagement was growing among scholars and educators around the world (Christenson et al., Handbook of research on student engagement. Boston: Springer Science & Business Media. doi: 10.1007/978-1-4614-2018-7, 2012). In this chapter, I describe the evolution of the engagement construct from high school dropout to a global construct for all kids, some lessons learned in school completion efforts, and the conclusion that student engagement and school completion are unifying constructs for educators and all interventions, policies, and practices within schools, corresponding with tiered models of support.