This qualitative research study explores high school teachers' perceptions of the factors influencing their self-efficacy during emergency remote teaching (ERT) in response to the COVID-19 pandemic. The study, conducted in a New Jersey high school, investigates the immediate transition from traditional in-person instruction to fully remote learning. By utilizing semi-structured interviews, the research focuses on five emergent themes: Adaptability and Flexibility, Student-Centered Approach, Communication and Transparency, Resourcefulness and Connection, and Challenges and Uncertainty Management. The research study aligns with Albert Bandura's self-efficacy theory, examining how mastery experiences, vicarious experiences, social persuasion, and physiological arousal contribute to teachers' self-efficacy during ERT. The findings suggest that teacher self-efficacy manifests in diverse forms. The research reframes teacher self-efficacy as adaptable and amenable to strategic cultivation, providing a comprehensive framework for promoting, supporting, and nurturing diverse facets of self-efficacy in the face of unprecedented challenges. This research study contributes valuable insights for K-12 administrators, offering qualitative data to inform future planning, preparation, and implementation of best practices during emergency school shutdowns. The multifaceted understanding of teacher self-efficacy presented in this research underscores the importance of recognizing and cultivating diverse forms of self- efficacy for sustaining effective teaching practices. [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.]