<p>This paper describes (a) the first studies to show that purposeful development of implementation capacity is possible in complex state education systems, (b) the first repeated assessments of state capacity development in education, and (c) the first to show purposeful capacity development can be replicated across departments of education in states that are unique in terms of history, size, and operations. This paper documents the culmination of ten years of development to improve education systems, organizations, and outcomes. With a focus on implementation and the Active Implementation Frameworks™, intensive support is provided to develop implementation capacity and scaling infrastructures in state education systems to initiate and mange change processes at state, regional, and district levels. Measures of implementation capacity monitor progress and inform action planning. The results from 5 states in Study 1 were encouraging and provided the opportunity to engage in improvement activities for capacity development methods and measures. The results from 5 states in Study 2 provide evidence of consistent and relatively rapid progress in capacity development replicated across states. Implementation practice and science are significant additions to efforts to improve education in the United States.</p>