In recent years, preventing and mitigating financial risks has been a core priority for advancing high-quality economic and social development. Within this context, effective management of corporate earnings volatility occupies a strategic and irreplaceable position in the financial risk prevention framework. Against this backdrop, embedding into platform ecosystems—a key mechanism for corporate strategic transformation—has emerged as a significant practical pathway for mitigating earnings volatility. However, existing literature primarily focuses on the impact of platform ecosystem embeddedness on corporate innovation efficiency, operational performance, and internal governance structures. A systematic research framework examining its mechanisms in regulating earnings volatility remains underdeveloped. Using panel data from listed companies between 2012 and 2023, this study empirically investigates the impact of platform ecosystem embeddedness on corporate earnings volatility. The findings indicate that such embeddedness effectively reduces earnings volatility, a conclusion that remains robust after a series of tests, including the instrumental variable method and the Propensity Score Matching-Difference in Differences (PSM-DID) method. Mechanism analysis reveals that engaging in diversified operations and improving total factor productivity are crucial channels through which platform ecosystem embeddedness mitigates earnings volatility. Additionally, public data openness further strengthens this mitigating effect. Heterogeneity analysis shows that compared to growth-stage firms and labor-intensive enterprises, the volatility-reducing effect of platform ecosystem embeddedness is more pronounced for mature-stage firms, decline-stage firms, and capital-intensive enterprises. Compared with existing literature, this study makes three marginal contributions. First, it expands the interdisciplinary research on the platform economy and the development of a financial powerhouse by integrating platform ecosystem embeddedness and corporate earnings volatility into a unified analytical framework, thereby enriching the perspective on corporate earnings volatility in the digital economy era. Second, by constructing a transmission mechanism model centered on “diversified operations–total factor productivity” and analyzing the moderating role of public data openness, it clarifies the pathways through which platform ecosystem embeddedness influences earnings volatility. Third, through heterogeneity analyses based on corporate life cycle and capital intensity, it reveals the differential effects of such embeddedness across firms with varying characteristics. This study systematically explains the causal chain and transmission pathways through which platform ecosystem embeddedness mitigates corporate earnings volatility. It not only provides methodological insights for earnings management within modern corporate governance systems but also offers a scientific basis for government entities and market participants to formulate differentiated governance strategies. Furthermore, it supplies micro-level driving force for the in-depth implementation of the financial powerhouse strategy, ultimately contributing to the steady realization of the socialist modernization goal in the financial sector.