At times, local politicians are described as barriers to interlocal cooperation; however, recent studies show elected officials are active in interlocal networks and harbour diverse motivations for their involvement in interlocal politics. This research introduces institutional role theory to the study of interlocal politics. Using a survey of elected officials in the San Francisco Bay Area, support for various roles in interlocal politics are assessed in relation to the scope of elected officials’ concerns about the use of interlocal agreements, as well as variables related to institutional context. Exploring elected officials’ concerns about interlocal agreements and the roles they undertake in interlocal politics sheds light on the democratic underpinning of metropolitan civil society and highlights new research opportunities at the intersection of public administration, political science and urban studies.