In 2013, the municipality of Gothenburg appointed two ‘process managers’ to temporarily reactivate an old harbor in the heart of the city, transforming it into Jubileumsparken (Eng. the Jubilee Park)—the first step in the broader RiverCity urban regeneration project. Over nearly a decade, Segerlund and Nilsson turned Jubileumsparken into one of Gothenburg’s most dynamic public spaces. They curated a process characterized by prototypes of spaces and services involving various actors, such as institutions, designers, collectives, artists, associations, and volunteers. This prototyping work proved capable of staying with and taking advantage of the many uncertainties it encountered, fostering a lively disorder in the course of its actions. This contribution examines this lively disorder, with a particular focus on the tensions between the prototyping process and the long-term planning of Frihamnen. While initially conceived as a dynamic and iterative process of learning from prototypes, the long-term planning process proved slow and contradictory. By critically reading the case of Jubileumsparken, this article contributes to a broader reflection on how practitioners cope with disorder while working on public space planning and design processes.