Design practices are being increasingly adopted by governments worldwide. Yet, barriers to design practices have been noted. Among the various barriers identified, a recurring theme is the gap between design practices and the established work practices of governments, suggesting that changes are needed on both sides—government organizations and design practices. In this paper, we present a study about how design practices become stabilized in the long term within local government organizations, drawing on organizational theory. The findings reveal that different types of legitimacy for design practices—pragmatic, moral, and cognitive—were shaped over time in different organizations, closely tied to each organization’s context and needs. Moreover, how design practices were interpreted and legitimized within an organization influenced what organizational processes and structures were developed to support them. This study demonstrates that the stabilization of design practices within government organizations is an adaptative process between the organization and design practices. We argue that this process is facilitated by the continuous efforts of design stakeholders in the organization.