This paper examines the client's decisions and actions taking place in the early project planning phase that could promote a circular economy in mid-rise timber construction projects. During the early planning phase, the client has an integral role in setting targets for circularity that the assembled construction actor-network carries out and tries to accomplish. However, the current research lacks concrete conceptualization and categorization of how circular economy principles can be carried out by the client in mid-rise timber projects. Therefore, the paper analyses one mid-rise timber construction project that has promoted circularity in all the life cycle stages. The study is conducted using a qualitative single case study method to identify which actors, resources, and activities can be utilized in the construction actornetwork to achieve circularity targets set in project brief. The main finding is that a single actor in the construction actornetwork has limited resources to promote circular economy in a mid-rise timber construction project and collective activities among project members are required to achieve circular economy targets. To conclude, the paper adds to the existing research by clarifying the client's role in utilizing the full circular economy potential of the construction actornetwork.