Participatory budgeting originally aimed to promote greater political representation and resource distribution for vulnerable populations. As it globally circulates, however, existing literature points out that its local interpretations and implementations often fall short of proper tools and mechanisms to advance its emancipatory potential. So far, the roles of different actors, objectives, and toolkits that contribute to diverging local experiences and outcomes have been widely studied. In contrast, extant research has rarely addressed the implications of different spatial contexts and their challenges—and the implicit potential—considering the distinctive institutional arrangements and opportunity structures at the urban scale. This article investigates how the policy idea of participatory budgeting landed in Vienna at the district level in 2017 (Partizipatives BürgerInnen-Budget), its outcomes, and how it evolved into a city-level project for climate change adaptation (Wiener Klimateam). It explores how the local institutional and structural conditions—including the political backing for such initiatives—influence the motivations, expectations, and experiences among different governmental stakeholders at multiple governance levels, shaping place-specific outcomes of participatory budgeting. It unpacks the specific opportunities and constraints of the deployed participatory tools in budgeting processes, according to three core values of democratic governance (legitimacy, justice, and effectiveness). The conclusion discusses the potential trade-offs between these three dimensions and argues that the current form of participatory budgeting in Vienna may increase legitimacy in the process but have less of an impact on the effectiveness of the delivery and the empowerment of vulnerable populations in the outcome.