The Earth is experiencing rapid and extensive environmental changes at an unprecedented scale. Human-induced changes in climate, biological and physical processes, and habitat extent and distribution have resulted in profound transformations in the structure and function of ecosystems. From cities to mountaintops to coral reefs, ecosystems across the globe are now characterized by emerging novelty in the form of unprecedented habitat patterns and species assemblages. In this context of uncertainty and novelty, it is more challenging than ever to re-establish functional, resilient, and climate-adaptive systems. Conservation and restoration have relied traditionally on historical knowledge as the basis for making informed choices. In an era of profound change, how will history matter? How should restoration or management goals and targets that are appropriate for a given place be chosen? What does success look like? This symposium explores the role of historical knowledge in shaping ecosystem management and restoration decisions for novel ecosystems. Historians and ecologists from academic and applied settings will discuss how historical knowledge is inspiring innovative approaches for managing forested, urban, marine, estuarine, and riverine ecosystems in the face of future changes. Far from being irrelevant in the face of rapid environmental change, an interdisciplinary collection of historical ecologists and environmental historians argue that an understanding of past ecological conditions, functions, and processes remains vitally important for identifying restoration strategies that leverage local potential.