As global educational landscapes undergo rapid transformation, the mental health of educators has emerged as a critical determinant of institutional efficacy and student success. This review article examines the multifaceted challenges faced by school teachers, framed within the context of the evolving 21st-century workplace. While teaching has historically been recognized as a high-stress vocation, the post-pandemic era has introduced unique stressors, including "technostress," administrative intensification, and a burgeoning "emotional labor" gap. By synthesizing contemporary research (2020–2025) and foundational literature (pre-2020), this article identifies the primary barriers to a thriving teaching workforce: namely, systemic workload issues, professional isolation, and the absence of robust institutional mental health support. The review moves beyond a deficit-based model (focusing solely on burnout) to explore innovative, salutogenic pathways. It highlights successful global policy interventions, such as the integration of Social-Emotional Learning (SEL) for staff and "well-being-by-design" institutional frameworks. Findings underscore that teacher well-being is not merely an individual responsibility but a systemic necessity. The article concludes by proposing a holistic framework—The Pathway to a Thriving Educational Workforce—which integrates digital literacy training, institutional psychological safety, and workload reform.