This study investigates the impact of integrating AI-powered tool, Plang, on English language learning among Korean EFL learners. Specifically, the study aims to examine the overall experiences of using the AI app in language learning and the impact of using the AI app on learners’ autonomous learning. The two-month study employed a qualitative data approach derived from a mixed-method study involving pre- and post-survey, reflective journals, and in-depth individual interviews. Overall, the findings have shown that the integration of the AI-powered tool into the English language learning helped learners: (i) to enhance language skills, particularly speaking proficiency; (ii) to foster learner autonomy through a personalized feedback system; and (iii) to establish a new goal that facilitates active learner engagement. The analysis also points out some challenges learners faced in the learning process. Some important implications of this study are discussed for teachers who consider integrating AI-powered tools into English language teaching. Considering that there has been little research on incorporating AI tools into classrooms, it is recommended that further research should highlight more dynamic classroom cases by developing a flipped classroom model utilizing AI tools in English language teaching contexts.