High school computing education reform efforts have been ongoing across the United States, particularly in the past decade. Although national Computer Science (CS) for All initiatives are promising, states retain control over education policies. Recent computing education reform efforts in the state of Maryland (U.S.A.) focused on providing every public high school student with access to high-quality high school computing courses. Such access provides exposure to computing careers and better prepares a diverse pool of students for computing majors in college and the workforce. This comprehensive embedded multi-level case study examines the state's computing education reform efforts from 2010 through 2016. The expansion of computing education indicates that while there was positive growth, the growth was not the same for all categories of public high school students. Top-down policies assist in providing leverage to elevate the need for CS; however, bottom-up efforts to support students and to enable teachers to retain autonomy and professionalism is also needed for CS expansion. Despite successes, barriers at the state, Local Education Agencies (LEA), school, and classroom levels persist and are discussed. The findings in this study can be applied to other states with similar governance structures and policies, and we provide specific recommendations.