Sustainable entrepreneurs face the challenge of aligning multiple, sometimes conflicting social, environmental, and commercial demands during their venture creation, shaping the business model design process in unique ways. This study explores these processes by conducting a multiple-case theory-building approach examining six nascent sustainable ventures (including 45 interviews) in a longitudinal research setting. We derive a process model depicting the dynamic interplay between a founding team’s cognitive configuration and their business model design approach. Specifically, we propose two distinct sustainable business model design process paths which largely depend on the cognitive frame (narrow vs. paradoxical) of a founding team. The insights from our framework contribute to the literature at the intersection of sustainable entrepreneurship, business model design, and entrepreneurial cognition.