Academic Summary: Recombinant innovation—the process through which atypical and unexpected combinations of knowledge generate novel outcomes—is a critical driver of organizational distinctiveness and market transformation. While prior research has focused on firm‐ and industry‐level mechanisms, less attention has been given to multilevel dynamics underpinning the mobilization of old knowledge for innovation. Through a longitudinal case study of Aboca, a firm that systematically integrates centuries‐old herbal remedies with evidence‐based medicine, we develop a process model of recombinant innovation starting from old knowledge. This model delineates the phases through which actors mobilize old knowledge for innovation and the mechanisms enabling transitions across these phases—recovering, reviving, and renewing—which appear as interconnected, each building upon the preceding one, enabling a dynamic and iterative mobilization of old knowledge. By integrating three levels of analysis—individual, organizational, and industry—our model provides a cohesive multilevel explanation of recombinant innovation. This study contributes to research on knowledge recombination and strategic renewal, offering insights into how organizations transition from individual‐level knowledge recombination to firm‐wide and industry‐level innovation strategies. Managerial Summary: Many organizations overlook the strategic potential of old knowledge, seeing it as outdated or irrelevant. This study shows how firms can turn historical insights into innovation by following a structured, multilevel process. Based on a case study of Aboca, a healthcare company that combines centuries‐old herbal remedies with evidence‐based medicine, the research identifies three key recombinant innovation phases: recovering, reviving, and renewing. First, companies systematically recover and digitize historical materials—books, recipes, artifacts—and organize them into accessible knowledge bases. Second, they form cross‐functional teams that include historians and scientists to reinterpret this knowledge and challenge existing assumptions. Finally, innovations are scientifically validated and repositioned in emerging market spaces, aligning with regulatory standards and consumer expectations. This process not only generates novel products but can also create entirely new product categories. For managers, the key lesson is that the past can be a rich source of innovation—if treated as a dynamic resource rather than a nostalgic reference. Firms in industries such as food, wellness, fashion, or cosmetics, where tradition adds value, can gain a competitive edge by combining old knowledge with modern science, crafting a unique innovation narrative that resonates with both regulators and consumers.