In recent years, the corporate innovation ecosystem has emerged as a purposeful architecture for the development of endogenous innovation and for systematic interaction with external actors, including startups, universities, investors, and intermediary institutions. Using thematic analysis and interviews with innovation managers from five major Iranian companies and field experts, this study explores key ecosystem dimensions: rationales, components, implementation mechanisms, obstacles, and the government's role. Findings show that ecosystem development is a gradual, context-dependent process that requires alignment with corporate strategy and organizational maturity, the institutionalization of agile structures, and cultural transformation toward open innovation. At the firm level, mechanisms such as innovation centers, innovation diplomats, corporate venture capital, and collaborative models with universities and knowledge-based enterprises generate tangible value when linked to the value chain and technological needs. Major challenges include governance deficiencies, policy instability, cultural resistance, weak absorptive capacity, lack of specialized skills, absence of trust and social capital, and dependence on government support. At the macro level, the government's role is not as a direct patron but as a facilitator and institutional enabler through consistent policy implementation, smart financial and tax incentives, strengthening private institutions, and developing infrastructure for synergy and connectivity. Ultimately, the findings underscore the necessity of transitioning from closed to open innovation and designing integrated policy and firm-level strategies tailored to the context, as a prerequisite for successful development of corporate innovation ecosystems in Iran.