The purpose of this research was threefold. First, the study explored the possible relationship between the tenure of public school district superintendents and the sustainability of their reform efforts to improve student achievement. Second, the study compared superintendents' perceptions of factors supporting or impeding sustainability of their reforms to elements identified in research. Third, the study sought to determine the extent, if any, to which superintendents considered sustainability when initiating reforms. A mixed-methods design was employed to combine theoretical and technical components of qualitative and quantitative analysis. Quantitative data from 51 southern California superintendents were collected via an online survey. Four southern California superintendents and 1 northern California superintendent were interviewed to obtain qualitative data. Analysis of the data indicated that, while the superintendents perceived a strong correlation between their tenure and reform sustainability, they noted that this correlation diminishes over time as reforms gain traction through broader support and acceptance. With regard to current reforms within their school districts, the superintendents recognized some but not all of the eight research-based elements deemed necessary for long-term sustainability. Finally, the data indicated that the superintendents considered sustainability when initiating reforms and were highly optimistic about their reforms lasting the test of time despite research and experience that might indicate otherwise. Implications for practice included efforts to minimize position turnover through differentiated strategies for recruitment and selection of superintendents, targeted professional development around the nature of reform sustainability, and possible linkages among lifespan development, reform initiation and durability over time. [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://www.proquest.com/en-US/products/dissertations/individuals.shtml.]