Abstract: | This article develops an ecological theory that shifts the paradigm of professional mobilization from causes to relational spaces. It analyzes different species of activist professionals by locating them in an ecology of activism and examining how collective action emerges from their boundary work with the ecology's increasing density and consolidation. It empirically grounds the theory by explaining the political activism of Chinese lawyers in the early twenty‐first century and how it led to a government crackdown in 2015. Using interviews, online ethnography, and archival data collected from 2005 to 2017, the research demonstrates that Chinese lawyers’ political mobilization has experienced three stages: (1) vacancy and isolation (2000–2007), (2) spatial consolidation (2008–2011), and (3) boundary work (2011–2015). The study has implications for theories of social space and for understanding professional mobilization in authoritarian contexts and beyond. |