This research focuses on leadership decisions by high school administrators in Maine in response to school closures and subsequent reopening plans due the Covid-19 pandemic. The purpose of this study was to learn the degree to which adaptive leadership was used as a leadership approach in response to a unique, complex and dynamic set of challenges, and to discover how the theories of constructive development influenced administrators' comfort with adaptive work. Adaptive leadership is identified as the focus for this study based on the unprecedented magnitude of adaptive challenges caused by the Covid-19 pandemic for school systems throughout the state of Maine. High schools were intentionally chosen as the environment for inquiry due to organizational dynamics this study identifies as a barrier to adaptive leadership (Bowles & Gintis, 1978). To understand how high school administrators led during the Covid-19 crisis, the researcher interviewed fourteen principals throughout Maine using a two-part interview protocol. The first part focused on the administrator's professional history and development as a school leader, while the second part was conducted to better understand how administrators implemented collaborative and adaptive leadership strategies from the months of March 2020 to the reopening of schools. Interviews were transcribed and coded for emerging themes related to adaptive leadership and cognitive development theory. [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.]