Objectives: The study aims to investigate the efficacy of the Poe ChatGPT-based TPACK model on EFL teachers' performance and their students' vocabulary learning. Methods: I designed four instruments to gather the research data: a survey of EFL teaching skills, a teaching knowledge test, an observation checklist for assessing teacher performance, and a vocabulary knowledge test. Results: The statistical analysis of the research data proved that EFL teachers developed their teaching performance. The statistical analysis of preparatory students' vocabulary tests proved no differences between the experimental and control groups. Conclusions: Utilizing the Poe ChatGPT-based Technological Pedagogical and Content Knowledge (TPACK) model positively impacted teaching skills. The impact of Poe ChatGPT on developing students' vocabulary learning was rejected. Implications: There is a need for future studies to examine the effect of Poe ChatGPT on secondary and university students' vocabulary knowledge and teachers' inquiry, critical thinking, and digital literacy skills.