The significance of the role of school administrator has been shown in recent years to be second only to the influence of the classroom teacher in terms of increasing student achievement and improving the climate and culture of a school. In recent years, teachers and administrators alike have been leaving the educational profession in large numbers due to burnout, challenging work conditions, and, more recently, the COVID-19 pandemic. Most research on school administrators neglects the essential but often invisible role of the assistant principal (AP). This mixed-methods research study explores the following research questions: (a) What are the greatest contributors to burnout for secondary assistant principals? (b) How are preparation, mentorship, feedback, and district infrastructure related to secondary assistant principal job satisfaction and outcomes? and (c) How does the secondary school administrator experience differ between Title I and non-Title I schools? I sent quantitative surveys to 756 principals and assistant principals in four San Francisco Bay Area counties, and received complete responses from 90. Fourteen assistant principals were also interviewed in order to gain rich qualitative data regarding how various factors influenced their job satisfaction and experiences. Correlational analyses indicated that strong principal relationships, feedback from principals, the presence of a formal evaluation, and the presence of district support all significantly contributed to higher levels of AP job satisfaction. The interview data analysis and sample t-tests also found that APs working in Title I (high poverty) schools experienced lower job satisfaction, less frequent principal feedback, less support from their districts, and had experiences their first year that were harder than their expectations compared to their counterparts working in low-poverty schools. [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.]