We present the American State Administrators Project (ASAP), a decades‐long survey of state agency leaders. This remarkable dataset provides a 50‐state chronological portrait of state administrative leaders, what they think, and what their agencies do. The dataset has traditionally been closely held but is now being shared with the broader scholarly community for the first time. We use this article to demonstrate the dataset's potential to advance theory and knowledge of the modern administrative state through the example of principal‐agent theory. As we show, the ASAP data allow us to reorient scholarship away from an empirical focus on how the president/governor, legislature, and other political principals try to influence the bureaucracy and toward a fuller appreciation of how bureaucrats formulate and administer public policy in a political environment. Such a refocusing is critical because it better recognizes the “agency” held by bureaucratic agents within modern governance.