This interview study explored the experience of principals as they mediate reforms marked by high-stakes accountability and competition between schools at the intersection of gentrification occurring in their school communities. School principals of high schools within New York City are called to mediate mandated school choice with the continued increase of school options and gentrification. Many studies examine a single phenomenon or policy but often these policies are "bundled" in complex ways, forming reform regimes, such as New York City's diverse provider regime. How principals balance multiple policies in a shifting demographic context remains an area ripe for exploration. This study investigated how principals perceive this market regime and how it has influenced their role, especially within gentrifying urban spaces. The findings of this study center on the professional dilemmas of school principals as they mediate the micropolitics of a market regime, while navigating policy shifts of new mayoral administrations and demographic changes in neighborhoods that have the potential to change the makeup of the communities they serve. Principals in the study fell into three categories in their response to gentrification in their school community: (1) principals who viewed gentrification as a threat, (2) principals who viewed gentrification as an inevitable reality, and (3) principals who viewed gentrification as an opportunity. Their responses shaped the experiences of both longstanding residents and gentrifying families in their schools. Additionally, principal experiences were also shaped by mayoral administration that influenced admissions, recruitment and expectations of how principals should run their schools. These findings indicate that principals must deliberately and thoughtfully respond to changes in the educational landscape, with a particular eye towards how race and class interact, whether it be through administrative changes or demographic changes, in order to equitably and fully serve their students. [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.]