A multi-institution project was implemented with the goal of improving science education through redesigned courses, inquiry-oriented pedagogy, and outreach to public schools. We examined the nature of faculty grassroots leadership in science education reform in the four main higher-education partners of the project: a community college, a master’s level university, and two different research universities. The main focus of the study was the interplay and role of top-down leaders in positions of authority (typically administrators) versus grassroots leadership among faculty and how these two converge and interplay to create organizational change. The convergence of bottom-up and top-down leadership is affected by institutional culture and context. Cross-comparative findings from the four cases are presented, including the context for change in each case, the role of administrative leadership on each campus, factors that either facilitated or hindered the emergence of faculty grassroots leadership, and the institutionalization and sustainability of these reforms. We then address the broader implications of the study with respect to understanding how grassroots leadership and traditional forms of authority and leadership can complement each other and facilitate organizational change. We contend that faculty grassroots leadership emerges on different campuses when there is sensitivity to the contextual differences. In particular, some attention needs to be given to the campus culture and the nature of faculty interactions at that site. The context for change at each institution and the role of administrative leadership and support shaped the conditions under which faculty grassroots leadership had emerged and, ultimately, the degree to which it was sustained over time. In addition, the faculty ownership of this project was essential to its success because, ultimately, the faculty needed to embrace the goals of curricular redesign and inquiry-oriented pedagogy for the desired institutional changes to be sustained.