During the COVID-19 pandemic, global teachers gained extensive experiences with teaching online courses. To design quality online courses in the post-pandemic era, the impact of the latest technology, such as artificial intelligence (AI), must be considered. Investigating how teachers incorporate AI-powered tools and how students perceive learning experiences with the tools is crucial for informing effective online course design. In this case study, we presented an 18-week online English course for 43 senior high school students in Taiwan. Designed according to learning theories, this course aimed to cultivate autonomous EFL learners, who learned to read and write with the support of three AI-powered tools (i.e. Linggle Write, Linggle Read, and Linggle Search). Data were collected from the instructors and students in both qualitative and quantitative formats. Results showed that a learning loop was created to connect online learning with offline practice; students had better optimal experience in student-centered presentations than in teacher-centered lectures; and language proficiency predicted semester grade and assignment quantity. This study has both theoretical and practical value; it serves as an example of how to design a quality synchronous online course on AI tools for EFL reading and writing based on theoretical approaches.