Collaboration involving large variety of actors across sectors, industries, and institutional settings have become prevalent in searching and creating new knowledge for variety of wicked and complex problems. These fluid forms of collaboration – labelled as knowledge ecosystems – allow organizations to collaborate with other organizations and individuals in a quest to search for and create new knowledge. The literature has thus far helped recognize the prevalence of knowledge ecosystems and their potential benefits, but is relatively silent on their origins and emergence. To bridge this gap, in this paper we theorize knowledge ecosystems as meta-organizations that pursue organizationality via establishment of organizing elements that aim for joint search of new knowledge. By virtue of this foundation, we analyze a longitudinal case study of High-Capacity Transport ecosystem in Sweden, and demonstrate the key organizational elements that emerged over the course of over ten years. We distinguish a process model explaining how three elements of organizationality in a knowledge ecosystem – participation, identity, and actorhood – emerge sequentially and by building iteratively on each other. The process model contributes to the theory, practice, and policy of knowledge ecosystems emergence.