Throughout history, artificial intelligence (AI) has impacted various aspects of human life and professional industries, including the field of education, by mimicking human behaviors and tasks to increase productivity and efficiency (Grudin et al., 2023; Haenlein & Kaplan, 2019). Generative AI is a form of AI using deep learning to quickly generate text, images, music, and endless types of content based on datasets training it. The training data is gathered from a corpus of information on the internet (Javaid et al., 2023; Ngo, 2023; Rahman & Watanobe, 2023). In 2022, generative AI became accessible to individuals of all ages and backgrounds when the company OpenAI launched ChatGPT works (Javaid et al., 2023; Ngo, 2023; Rahman & Watanobe, 2023). Educators began to use generative AI to plan instruction, create materials, and complete daily tasks more efficiently (Alabool, 2023; Fisk, 2023; Rahman & Watanobe, 2023). Students began to use generative AI to assist with schoolwork, studying, proofreading, and creating content for school (Hosseini et al., 2023; Ray, 2023b). Concerns about quality, accuracy, bias, academic integrity, and data security surfaced among educators as the use of generative AI increased (Abramski et al., 2023; Eke, 2023; Perkins, 2023; Ray, 2023b; Su & Yang, 2023). As educators navigated the opportunities and pitfalls of generative AI in teaching and learning, a need to understand educators' perspectives of the phenomenon became necessary. This study, therefore, holds significant value in providing insight into the experiences and perceptions of secondary teachers on using generative AI as a tool for teaching and learning. This qualitative, phenomenological study explored the perceptions of secondary teachers on using generative AI as a tool for teaching and learning. The researcher conducted semi-structured interviews with ten teachers of core subjects (science, social studies, and English language arts) in grades 9-12 from western Pennsylvania schools, seeking insight into experiences with and perceptions of generative AI in schools focused on five research questions: (a) How do teachers of students in grades 9-12 core content courses see generative AI being used in schools in Western Pennsylvania? (b) What do core content teachers of students in grades 9-12 believe are the benefits of using generative AI in the teaching and learning process? (c) What concerns do core content teachers of students in grades 9-12 have regarding using generative AI in schools? (d) How do core content teachers of students in grades 9-12 perceive the level of preparation and guidance from school leaders on the use of generative AI in their school? (e) How do teachers perceive the impact of generative AI on students? The key findings noted teachers used generative AI to create comprehensive materials and communicate with stakeholders. Additionally, the findings indicated teachers are concerned about academic integrity, the quality of AI output, and the need generative AI presented to change classroom instructional practices. The key findings also revealed teachers need more targeted professional development on generative AI related to teaching and learning along with guidance from administration and policy and procedures for generative AI usage. The final key findings expressed concerns about students using generative AI to minimize effort while reducing the authenticity of learning experiences. These finding are supported by existing research. Additionally, the key findings support the notion that generative AI can support effective instruction when teachers are presented with targeted professional development, policies, and procedures and develop strategies that involve teaching effective methods to check the accuracy of AI output along with tools to detect academic integrity issues partnered with quality instruction about the importance of academic integrity. [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://bibliotheek.ehb.be:2222/en-US/products/dissertations/individuals.shtml.]