An increasing number of firms are aiming to implement closed-loop supply chain (CLSC) management to contribute to a more circular economy. However, for many of these firms, it is difficult to translate this strategic aim into fruitful operational decisions. They need to address many deep uncertainties and dynamic complexities in their supply chain system , which make their transition towards CLSC management challenging. This article aims to develop a better understanding of how supply chain actors taking steps towards CLSC management could be supported to reach higher levels of maturity in dealing with deep uncertainty and dynamic complexity. This is investigated in a single, facilitated, embedded case study: a future-oriented decision-making process regarding the use of timber with four real-world actors in the construction industry. The process is structured and supported with analyses, following a methodology based on the capability maturity approach. In this empirical context, the selected approach is shown to have positive effects on clarifying the potential impact of transitions to CLSC management. Furthermore, it stimulates important learning processes during the transition, and as such supports actors to achieve higher levels of maturity and to take further steps towards CLSC management. In this context, a conceptual distinction is made between 'situational maturity' and 'mental maturity', which enriches double-loop learning theory in the context of transitions.