This research assesses how professional expertise is constructed and deployed by public and private sector practitioners. In-depth case studies of urban design projects in two cities with differing local government capacities are used to critically examine professional expertise. The study finds that the expertise of consultants was portrayed as more creative and innovative, less constrained by bureaucratic and political contexts, and more knowledgeable of market conditions. In contrast, descriptions of public employee expertise often focused on regulatory knowledge. This study analyzes the relationship between limited public sector capacity and these constructions of expertise—and the implications for professional practices.