As Cornwall (2010) well summarizes, the concept of participation has evolved in theory and practice throughout the history of international development. In principle, this evolution has followed the history of the politicization of development, which worked to change the roles of state, market, community and civil society (Li 2001), as well as the conceptual definitions of individual agents and citizens. In other words, the nature of participation and participants has shifted in correspondence with changing assumptions about the location of power and agency. For example, at the beginning of international development, participation was not an outcome of participants’ exercise of agency but rather an outcome of the enactment of structural imperatives to achieve planned development. Over the years, the participants’ agency has been recognized but in different degrees, and we need to explore how to engage in mobilizing agentive participation fully in realizing transformative sustainable development. This chapter reviews chronologically the process of shifting power and agency in international development with reference to social theoretical debates on the reflexivity focus. In particular, it pays attention to the ways that the agenda of sustainable development influenced this process, as it shaped an “intellectual heritage” of development thinking and actual aid policies (Conroy and Litvinoff 1988; Crewe and Harrison 1998). By doing so, the chapter intends to highlight what the focus on corporeality and material for transformative change seeks to address vis-à-vis existing assumptions about ecological rationality and citizenship, which have been increasingly adopted in actual sustainable development projects.