This paper seeks to better understand the way staff professionals bring professional practices inside their organization by examining how they enact a practical agency to promote or disrupt practices. From an inductive study of occupational safety and health managers in a multinational construction company, we develop a framework of how staff professionals build perceived legitimacy and exert unobtrusive influence tactics to manoeuvre around social constraints. We contend that our principal contribution to the literature on institutional work is to provide a situated account of the practical agency of staff professionals inside one organization. In doing so, we extend current knowledge of the embedded agency paradox. Finally, our analysis offers new insights into the literature on professions and institutions by highlighting the work of staff professionals in a real‐life context, which has received scant attention in the last three decades.