This qualitative, phenomenological study examines how artificial intelligence (AI) impacts lesson design for teachers at a school district in southeast Texas. As generative AI becomes more integrated into education, this research investigates how AI tools influence teachers' abilities to create dynamic, differentiated, and effective lesson plans. Through individual interviews with teachers who use AI in their teaching practices, the study identifies the perceived benefits and challenges of using AI in lesson design. Key findings show that AI enhances accessibility, idea generation, professionalism, and efficiency, while also boosting teachers' confidence, self-efficacy, and content knowledge. However, the study also uncovers concerns about ethical issues such as data privacy, AI reliability, and the risk of cheating. The thematic analysis of interviews reveals the transformative potential of AI in education, offering insights into its role in assessment, differentiation, and fostering innovative teaching practices. The results provide practical applications for educational leaders aiming to leverage AI in curriculum development and teacher support. [The dissertation citations contained here are published with the permission of ProQuest LLC. Further reproduction is prohibited without permission. Copies of dissertations may be obtained by Telephone (800) 1-800-521-0600. Web page: http://www.proquest.com.bibliotheek.ehb.be/en-US/products/dissertations/individuals.shtml.]