This article analyzes the formation of the largest grassroots social movement in Brazilian history: the Movement of Rural Landless Workers (MST). In movement literature and academic discourse, MST's formation has been consistently attributed to three factors— agricultural restructuring, political transition, and religious organization. These three factors form what I call an "Official Genesis Story." I argue that although the Official Genesis Story fits together well at the macro level, it cannot explain who decided to join MST or why, because the story does not locate acts of resistance in either people or place. A comparison of MST members in two different regions of Brazil shows how the spatial constitution of production and reproduction informed individual decisions to join MST. By geographically situating the official story, we uncover the contentious actors behind the contentious actions.