Sustainability is a key societal challenge and has become an opportunity for innovation. While start-ups are prone to enter such new territories, established companies are more hesitant to leave current trajectories and embrace uncertainty linked to sustainability-oriented exploration. We present a case of a conventional high-tech firm of an owner-manager whose strong values of universalism led him to initialise a sustainability-oriented diversification by exploring renewable energy technologies. Our longitudinal study uncovers how changes in ambidextrous organisational design and represented managerial values ultimately resulted in failed exploration. Our contribution is threefold: First, we link individual-level managerial values of universalism with organisational-level phenomena of sustainability-oriented exploration and diversification. Second, we contribute to bridging hitherto mostly separate bodies of literature on sustainability-oriented innovation and ambidexterity to better understand how conventional firms can deploy their technological capabilities for sustainability. Third, we conceptualise the "separation drift"as fading organisational separation resulting in exploration failure.