Although much has been written about public sector innovation in the last two decades, we still do not fully understand how public sector organizations become innovative. Therefore, this study inductively explored how four Norwegian municipalities developed innovation capabilities. I found that public sector organizations develop two forms of innovation capability in a path-dependent manner: low-routinized innovation capability and highly routinized innovation capability. In the former, dynamic managerial capabilities in the form of individuals’ entrepreneurial and leadership skills comprise the source of innovation capability. In contrast, in the latter, innovation capability emerges from dynamic organizational capabilities, that is, a set of innovation-stimulating routines, processes, tools, and structures. Notably, I found that regardless of the form of innovation capability, both spur the continuous development and implementation of various radical and incremental public sector innovations. Based on these findings, this study offers several contributions to the literature on public sector innovation and to the dynamic capabilities research agenda.