Digital platforms have become the cornerstone of contemporary business models, orchestrating expansive ecosystems that drive value creation across multi-sided markets. Platform owners, however, confront a persistent strategic paradox: they must promote openness to fuel innovation, complementor participation, and ecosystem growth while exercising sufficient control to safeguard standards, capture value, and mitigate risks. This managerial and strategic perspective article examines the governance tensions inherent in expanding digital platform ecosystems. Synthesizing insights, it analyses governance mechanisms, openness–control trade-offs, ecosystem coordination challenges, platform owner–complementor dynamics, and the need for dynamic adjustment. Excessive openness risks fragmentation and value leakage, whereas excessive control can suppress innovation and trigger stagnation. A governance balancing framework is introduced that integrates openness configurations, control mechanisms, incentive alignment, ecosystem coordination, adaptive processes, and risk management layers. Practical guidance is offered on how platform owners can operationalize this balance as ecosystems scale, thereby sustaining competitiveness and long-term viability. The article underscores that effective platform governance is not a static choice but a continuous strategic discipline essential for thriving in digital markets.