The development of English as a Second Language (ESL) course books for young learners often presents significant challenges, particularly in sourcing texts that engage children both linguistically and culturally. Prior to the advent of ChatGPT, the author, a teacher educator, worked diligently to assist student teachers in creating mini-course materials through manual editing and refinement. However, the introduction of ChatGPT has markedly transformed this process, enhancing the ability to adapt texts, lower their difficulty levels, integrate essential grammar items, and pinpoint engaging content. This paper aims to share the author's experiences in developing materials for ESL classroom tasks. It begins with an overview of the study's context and a review of relevant literature. Following this, the paper outlines the strategies employed with student teachers for material production without the aid of AI. Lastly, it details the processes utilized to integrate ChatGPT into material development. The presentation aims to illuminate the innovative aspects of this approach and underscore the advantages of AI-assisted course book creation.