Business is a high-stakes game. Strategy is about ensuring that the organisation plays the right game in the right way. To do so, competitive advantages underlying the designed business model are identified based on answering Porter’s five strategy questions. The organisation’s competitive advantages describe its unique positioning among key players. In extension to traditional strategy schools embracing the competitive advantage approach, design thinking-based strategy development puts a strong focus on the role of the customer. To ensure the sustainability of the competitive advantage over time, a game-theoretic analysis is performed to develop possible competitive strategy game plans for reacting to external threats. A successful strategy identifies and attains a competitive equilibrium among all involved players, putting the organisation centre stage. The competition layer of the strategy design process defines this equilibrium by making the organisation’s competitive advantage explicit and proactively, rather than reactively, anticipating potential changes in the competitive environment over time.