The paper contributes at the debate on circular economy as emerging paradigm aimed to promote sustainable development patterns, by focusing on the issues of the innovation ecosystems and quintuple helix. Despite the topic of innovation results to be intrinsically linked to the paradigm of circular economy and the dimension of environmental sustainability is more and more recognized crucial into the debate on innovation ecosystems through the quintuple helix, the exploration of their meaning and dynamics in the perspective of circular economy is under-researched and calls for a deeper comprehension. Framed in the above premises, this paper presents the evidences of a single and extreme case study related to the Italian Circular Economy Stakeholder Platform (ICESP), as good practice of a digital platform for stakeholders’ engagement supporting the creation of an innovation ecosystem focused on the circular economy.