The current model of teaching where one teacher works individually with a group of learners in a classroom in an alternative educational setting promoted unrealistic expectations by assuming individual teachers working alone could meet the needs of all students. To address this problem, I conducted an action research study in which I explored the outcomes of a team-based teaching approach that was implemented to make the dramatic shift away from a traditional, industrial-like, one-teacher, one-classroom model that existed in the school. In the intervention, a teams-based approach was implemented where teachers worked in teams of four to collaborate on professional learning, determine students' needs, then plan and implement instruction for the same, group of students. A sample of nine educators at Riverview High School completed the Teacher Self-Efficacy Scale (TSES) and the Professional Learning and Teacher Attitude (PLTA) survey to assess self-efficacy for instruction, classroom management, and student engagement, and professional learning and attitudes in a team-based setting. Qualitative data consisted of interview data and data from four focus groups. Findings indicated teachers using the team-based model demonstrated increases in mean scores across the five constructs. Additionally, analysis of the interview and focus group data revealed four themes emerged, including a new school culture, meaningful professional learning, collegiality through collaboration, and increased professional attitudes. The discussion focused on complementarity of the quantitative and qualitative data and how use of the team-based model transformed how education was conceived and delivered at an alternative school for at-risk students. In addition, I described limitations, implications for practice and research, and concluding thoughts. [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.]