Of the myriad responsibilities of the building principal, the most recognized and critical activity is overseeing and ensuring student success in the classroom. Considering the diverse population of professionals that building principals have under their supervision that directly impact students' classroom learning, the authors posit that a critical and unrecognized contributor to educational achievement and success is the school nurse. The vital importance of the school nurse's role in students' classroom success can be found in the U.S. Department of Health and Human Services fundamental statement, "health is a foundational aspect of children's ability to develop, learn, and thrive" in the classroom. Therefore, in cooperation with a building principal's leadership, the formation of a mutualistic, trusting, professional, and visible relationship with the school nurse is vital in laying a foundation for successful student learning outcomes. Furthermore, the importance and criticality of a successful principal-school nurse relationship is supported in the tenets, directly or indirectly, found in "Whole Child" research and the "Every Student Succeeds Act." Finally, this vital relationship is found to be even more crucial during this period of the COVID-19 pandemic. [Note: The publication year (2020) shown via the full text is incorrect. The correct year is 2021.]