The purpose of this mixed methods case study was to examine the disproportionate distribution of substitute teacher coverage in a case study district and learn why substitute teaching jobs may be filled in some schools more than others. Utilizing an explanatory sequential design, the researcher aimed to determine why the variance in substitute teacher fill rates existed. By converging data trends and qualitative feedback, the researcher sought to better understand the motivation of substitute teachers and the impact their job selections have on school stakeholders. The findings from this study will support school systems in decreasing the variance in substitute teacher fill rates between individual schools. This will minimize inconsistencies that currently exist in students' access to substitute teachers, lessen disruptions to campus operations, and provide more continuity in instruction for students. The nuances surrounding substitute teaching were explored in this study, providing insights on how to improve the substitute teaching experience for the employees, students, and school community. As a result of the public-school challenges created by the COVID-19 pandemic, the demand for substitute teachers has increased and the supply has decreased. The motivation of substitute teachers willing to serve in schools is critical to explore so that administrators can be responsive to the findings and motivate substitute teachers to accept jobs in every school. [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.]