This dissertation is a multiple methods study that examines the role of both students and schools in Philadelphia’s high school application process. First, district administrative data of a cohort of eighth grade students in 2008-09 and school characteristics is used to examine students’ odds of high school application and admission. A two-level hierarchical generalized linear model is used to account for the clustering of students within sending schools and to determine the relative contribution of individual and school characteristics. Students who meet the seventh grade record criteria have higher odds of application and admission, but race, gender, special education status, and English language learner (ELL) status are also significant predictors. Further, students in K-8 schools have higher odds of application, and students in high poverty and persistently dangerous schools have lower odds of admission, controlling for other factors. Second, interview data of sending school counselors, parents, and students and observations of high school-related activities at 10 schools is used to answer questions about who manages the application process. Counselors employed two distinct strategies. In the “clearinghouse approach,” counselors were willing to help students, but the burden of information and decision-making is on families. In contrast, counselors who used the “brokering approach” raise students’ high school awareness in seventh grade and meet individually with students and their parents in eighth grade to decide where the child should apply, given their seventh grade record and interests. Students whose parents have less than high school education and students from immigrant families particularly benefit from the institutional supports of the brokering approach because they otherwise navigate the high school application process independently. Thus, the counselor approach is one mechanism through which schools can mitigate or exacerbate individual differences in information and the likelihood of high school application and admission. Overall, this study reveals that individual and sending school characteristics matter more than the school choice literature suggests. Students’ seventh grade record limits their high school options, but students with equal qualifications have unequal odds of admission in this system based on their background characteristics and school characteristics.