Reactive scheduling is essential for optimizing resource flows in the circular economy. This chapter explores agile scheduling strategies that enable real-time adaptation to disruptions and changes, ensuring efficient utilization of materials and minimizing waste. By leveraging dynamic resource allocation and closed-loop systems, organizations can build resilient supply chains capable of responding to evolving market demands and sustainability requirements. Key topics include supply chain agility, sustainable operations management, and material flow optimization techniques tailored for circular business models. The chapter provides practical insights and case studies demonstrating the benefits of reactive scheduling in driving the transition toward a more sustainable, circular future.