Generative AI (GenAI) is changing education by reshaping teacher roles and pedagogical methods. This study examines its impact on classroom interactions through an activity theory lens, highlighting the balance between GenAI’s benefits and the human aspects of teaching. Using a qualitative multiple case study approach, it explores how ChatGPT and TeacherMatic influence teachers' roles, pedagogical strategies, and classroom dynamics. Findings indicate that while GenAI improves personalised learning and administrative efficiency, it remains a complementary tool rather than a replacement for human mentorship and expertise. The study emphasises GenAI as an educational innovation that implants proven pedagogy, improving instructional efficiency while preserving essential human elements. These insights call for policymakers and technology-enhanced learning researchers to develop frameworks that optimise GenAI’s benefits without compromising holistic educational practices.