PT XYZ, a plastic packaging manufacturer in Indonesia, is highly exposed to seasonal spikes and supply chain disruptions caused by geopolitical factors. As a manufacturing organization, it increasingly operates in a dynamic environment characterized by fluctuations in demand and tight operational constraints. Employee adaptability is a key factor in successfully addressing these challenges, supported by technological systems such as ERP and MRP as enabling tools. This study examines how workforce agility—specifically through the dimensions of proactivity, adaptability, and flexibility—supports on-time order fulfillment amid fluctuating demand conditions. Using a qualitative case study approach, this research investigates the operational dynamics of the Production Planning and Inventory Control (PPIC) department and the Production department. The findings indicate that workforce agility at PT XYZ manifests as a balanced interaction between formal structures and informal mechanisms. To cope with fluctuating demand changes, employees demonstrate proactive cognitive sensing by leveraging historical data trends to predict and prepare for seasonal demand shifts before formal market orders are finalized. Additionally, the organization mitigates the rigidity of the formal ERP system and scheduling workflows by utilizing informal communication channels, such as WhatsApp groups, which significantly accelerates information velocity. This study contributes to the literature on operations management and human resources by empirically demonstrating that workforce agility is not merely an innate individual trait, but rather a socio-structural capability supported by proactive data literacy, two-way communication networks, and experience-driven relational values.