The purpose of this study is to describe and examine the structures and policies a public, comprehensive high school put in place to implement problem-based learning (PBL) across content areas. Starting in 2010, the school implemented PBL in the hopes of increasing students' career and college readiness skills. The research took place at a comprehensive, public high school in the Pacific Northwest that serves a racially, ethnically, linguistically, and learning ability-diverse population of students. In this mixed-methods study we share findings describing the impacts of PBL adoption on teacher learning, student learning, and students' career and college readiness. Qualitative data was collected during the 2010-2015 school years. To describe how the school implemented PBL pedagogy, we take a grounded theory approach to qualitative data collection including collection and analysis of teacher and school leader interviews, teacher focus groups, classroom observations, and document review. Quantitative data was collected from the 2002-2015 school years and was part of several exploratory studies meant to examine possible changes in student performance and changes in their career and college readiness using student achievement on Advanced Placement (AP) tests over time as our primary tool of measurement. We compare the mean AP scores of two groups of students, matched according to grade point average (GPA), free and reduced lunch (FRL) status, whether or not students speak a first language other than English at home, and students who qualify for Special Education accommodations (SWD). The first group of students (comparison group) attended the school for at least 3 years before PBL adoption and received no exposure to PBL curriculum or coursework. The second group of students (treatment group) attended the school for at least 3 years during and after the school had adopted PBL and received full exposure to PBL curriculum and coursework. Qualitative findings indicate that between 2010-2015, teachers gained and deepened their expertise in PBL pedagogy and principles in part due to redesigned professional learning experiences provided to teachers during that time. Quantitative findings indicate that students in the treatment group experienced gains on AP scores across multiple AP courses in all four core content areas. Notably, student gains on AP scores were statistically significant in AP Biology, AP Calculus (combined BC and BCAB), AP Chemistry, AP United States Government, AP Psychology, AP United States History, and AP World History. Students in the treatment group also experienced gains in AP pass rates overall that paralleled higher enrollment in AP coursework and increased numbers of AP tests takers. Lastly, the data suggest a strong correlation between the number of PBL courses students complete and an increase in mean AP scores throughout their high school career. While student gains in mean AP scores are encouraging and suggest PBL may augment student performance in AP coursework, more research is needed to further explore this relationship. Our data suggest that PBL-focused school transformation necessitates a long-term, school-wide, inside-out approach. Appendices include: (1) Implementing PBL Classroom Observation Protocol; (2) Key Element Classroom Observation Protocol; and (3) Levels of Use (LOU) Teacher Interview Protocol. (Contains 40 Tables and 39 Charts).