In this article the authors recount the history and challenges of implementing coaching in 153 Georgia elementary schools over the 6-year period of Reading First funding. After outlining the expectations of Reading First, they describe the particular demands of coaching in a reform setting and detail the formative lessons that allowed the program to evolve responsively. Each year progressed toward a more fine-grained focus for professional development. Beginning with broadly based knowledge building in Year 1, the project turned to building the capacity of coaches and state staff as data interpreters and professional developers in Year 2. Year 3 entailed a gradual release that enabled coaches and state staff to make more choices in order to tailor professional development to the needs of their schools. Based on longitudinal data, Year 4 narrowed the focus to interactive read-alouds (conducted to build comprehension and vocabulary) and small-group differentiated instruction. Because teacher response to implementing differentiation was positive, Year 5 involved a continuation of the efforts to refine and extend the use of read-alouds. The final year of funding was devoted to sustainability, including the creation of archived materials (available to all) and online modules. (Contains 1 figure and 3 tables.)