With the passage of the 1935 National Labor Relations Act (NLRA), the American labor movement cemented the right to form unions and engage in collective bargaining. However, the NLRA explicitly excluded the public sector. Government employees did not achieve similar legal protections until decades later, and even then, the laws varied considerably by state. Because of this, scholarly accounts of the development of public-sector unions usually start in the 1960s and emphasize how public- and private-sector unions developed along separate paths. In this article, we analyze a new dataset and show that hundreds of cities had organized workers during the 1920s, 1930s, and 1940s, including firefighters, police, and other public-sector workers (like those in the sanitation and roads departments). By the 1950s, numerous employee unions had engaged in strikes and had achieved written agreements with their city employers. We also present evidence that public- and private-sector employee organization were correlated during this period. Thus, despite very different legal contexts before 1960, our evidence suggests that the timing and location of early public-sector organization may have had more in common with private-sector organization than is often recognized.