This paper aims to explore how circular innovations can gain stakeholders’ support to be seen as legitimate. This paper positions circular economy as a boundary object and aims to explore the process through which it facilitates the legitimacy-seeking actions for circular innovation. Drawing on three UK circular-born start-ups, this paper underpins the need of gaining cognitive, moral and pragmatic legitimacy for circular innovation to reap sizable impacts and expounds the process through which a circular economy undertakes mechanisms to gain three forms of legitimacy. This paper argues for more nuanced understanding of abstract object such as boundary object in legitimacy-seeking processes.