Career academies, schools within schools that concentrate on career fields, require the intentional efforts of teachers working collaboratively and sharing best practices to increase students' achievement and employability. Little is known of the perceptions of career academies' teachers, however, as they attempt to make changes in practice. The purpose of this descriptive case study was to analyze teachers' experiences in their transitions to a high school career academy. Constructivism, organizational theory, and Vygotsky's theory of social development were used for the theoretical framework. The research question explored teachers' experiences as they transitioned to a career academy and their participation in organizational change. A purposeful convenience sample of 15 core subject and career and technical education teachers from one district was used for semistructured interviews. Field notes from observations of meetings and document analyses were also part of the case study data. Data were coded for key words and phrases as well as cause and effect statements and clarifying ideas. Member checking and triangulation were used to validate and strengthen the interpretation of the data. Results indicated that the teachers did not experience a noticeable change in their collaboration, curricula, or physical setting during the transition and perceived that the mix of career academy and regular students in their classes impeded the implementation process. Recommendations include the discrete scheduling of academy students and more involvement of teachers in the decision making. Deliberate program implementation, including greater teacher involvement, could result in positive social change in the district's academy students' postsecondary educational opportunities as well as improvement of career academies as a national school reform model. [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.]