This conceptual paper proposes a novel approach to English as a Foreign Language (EFL) teaching in Society 5.0, integrating Generative Artificial Intelligence (AI) through an ecological perspective. As technological advancements reshape educational landscapes, traditional EFL methodologies face challenges in meeting the evolving needs of learners. This study addresses this gap by introducing the Eco-Generative EFL (EG-EFL) model, a comprehensive framework that reimagines language learning as a dynamic ecosystem. The EG-EFL model leverages the capabilities of Generative AI to create immersive, adaptive, and personalised learning environments while maintaining a holistic view of the interdependencies within the educational system. Through a rigorous theoretical analysis and synthesis of existing literature, this paper explores the potential applications of Generative AI in EFL contexts and examines their ecological impact. The proposed model offers innovative strategies for enhancing learner engagement, autonomy, and language acquisition. Furthermore, this study discusses the pedagogical implications, technological considerations, and ethical concerns associated with implementing the EG-EFL model. By presenting a forward-thinking approach to language education, this paper contributes to the ongoing dialogue on educational innovation in the era of Society 5.0. It provides a foundation for future empirical research in AI-enhanced language learning ecosystems.