Organization and management scholars are increasingly interested in understanding how “fluid” forms of organizing contribute to the tackling of grand challenges. These forms are fluid in that they bring together a dynamic range of actors with diverse purposes, expertise, and interests in a temporary and nonbinding way. Fluid forms of organizing enable flexible participation. Yet, they struggle to gain and sustain commitment. In this case study of the SDG2 Advocacy Hub, which supports the achievement of zero hunger by 2030, we explore how the temporality of narratives contributes to actors’ commitment to tackling grand challenges in fluid forms of organizing. In our analysis, we identify three types of narratives—universal, situated, and bridging—, and discern their different temporal horizons and temporal directions. In doing so, our study sheds light on the contributions by the temporality of narratives to fostering commitment to tackling grand challenges in fluid forms of organizing. It suggests the importance of considering “multitemporality,” i.e., the plurality of connected temporalities, rather than foregrounding either the present or the future.