Education for Sustainable Development (ESD) and the use of Generative Artificial Intelligence (GenAI) are two emerging trends that have gained increasing attention in contemporary education. Several studies in STEM education have demonstrated that integrating ESD into learning topics is both feasible and meaningful. Other studies have also indicated that certain STEM topics incorporating artificial intelligence (AI) technologies can be effective, particularly when Science, Technology, or Informatics serves as the core subject. However, the integration of ESD and AI has received limited attention in STEM topics where Mathematics plays a central role. This paper adopts a narrative review approach, in which relevant and representative studies on ESD, GenAI, and STEM education in teacher education are selected and analyzed to synthesize the theoretical foundations for proposing a training process. The study proposes a training process based on the four-stage framework of Ingénierie de formation and extends it into six phases: (1) identifying required knowledge; (2) selecting integrative courses; (3) determining content, timing, and duration; (4) designing the training plan; (5) implementation; and (6) evaluation and refinement. The application of this process to the development of a training plan for pre-service mathematics teachers—aimed at simultaneously enhancing ESD content knowledge and GenAI technological competence within the TPACK framework—indicates its feasibility in design and implementation. The study contributes a structured and transferable training process for teacher education programs, supporting the integration of sustainable development and emerging technologies in K–12 STEM education.