City-regions have become a core unit of analysis for spatial economy, providing an explicit link between bounded administrative units and more networked spaces of production. Too often, however, such analysis is focused on the core of the city-region, applying presumptions of gravity-based agglomeration. This paper examines these networked spaces of production from the city-region periphery, using a firm-based approach as critical determinants of spatial economy via their key interactions. Focused on the Greater Birmingham city-region, UK, the paper explores the integration of city-regional geography with firm-based networked economy. In doing so, it applies a set of networks of practice, focused on firms’ factored, transactional, and transitional dependencies. Using these networks of practice, it critically analyses the spaces of production formed through firm-based interactions, and their concomitance with city-regional designations. It makes two key contributions. First, it enhances the call for greater understanding of the relationship between core and periphery in the context of city-regions. Second, it argues that network-based approaches, which form spatial economy around firm interactions over administrative configurations, offer useful insight into understanding firm–place relationships which more conventional place-based approaches cannot.