This study explores how generative artificial intelligence (GenAI) usage affects leadership in knowledge-intensive environments, examining both short- and mid-term impacts. Drawing on preliminary findings of an in-depth case study within a large insurance company, we identify that while short-term effects mirror traditional technology adoption challenges, mid-term impacts require significant shifts in leaders' role, leadership styles, skills, and attitudes. Leaders must evolve from technical experts to orchestrators of human-AI collaboration, emphasizing employee-centric leadership. Our results offer initial empirical insights for managers and HR departments to proactively recalibrate leadership development strategies, ensuring the sustainable realization of GenAI’s promised efficiencies and highlighting the need for a redefined understanding of leadership in the context of AI-equipped teams. Further research is required to close the existing gap in literature and practice.