This paper explores Illinois's shift from a general administrative license, called a "Type 75" license, to a "PK-12 Principal Endorsement." It includes both a history of the reform efforts and a look at how implementation has fared nearly a decade after the legislation was signed into law. It also offers lessons and recommendations for other states looking to ensure principals are equipped to lead pre-K and early grade classrooms. [For an overview of this report, see ED599867.]