In an urban, low-achieving district in the northeastern United States, a small school has adopted the Expeditionary Learning (EL) philosophy and pedagogical approaches to instruction. Between the academic years of 2012--2016 state-assessed student achievement scores were less than proficient and implementation reviews revealed that the school made little to no improvement in the core practice category of instruction over 4 years of EL implementation. The purpose of this qualitative case study was to answer guiding questions by examining 12 teachers' perceptions regarding EL instruction as a core practice and element of the annual implementation review, and the impact of EL instruction on student achievement. The study was guided by the EL instructional subcomponents. Using purposeful sampling, data were collected from questionnaires administered to 12 full-time EL teachers. Semistructured interviews and classroom observations were conducted with 3 of the 12 EL teachers. Thematic data analysis followed an open coding process to identify emergent themes. The findings revealed: (a) a relationship between confidence levels of teaching EL instruction and experience, (b) existing gaps in knowledge of instructional subcomponents, (c) variability in implementation of subcomponents, (d) full instructional implementation influenced by time constraints/professional development, (e) existing gaps in teachers' knowledge of implementation review driven goals, (f) professional development related to the implementation review, and (g) student academic achievement impacted by EL instruction. The study and project have implications for positive social change through guidance into improved instructional practice and higher student achievement.