Instructional leadership is conventionally viewed as a principal's responsibility, practiced within a school distributed leadership configuration or other framework of school leadership. However, principals deliberately and visibly support teacher efforts in exerting leadership as teacher leadership practices are implemented for the improvement of student outcomes. This study reports on an in-depth analysis of the perceptions of instructional teacher leadership practices in public schools across the Eastern Seaboard. The instrumentation used captures descriptive accounts of leadership practice from seven teacher leaders who participated in the DOE Ambassador Fellowship program. They met the educational leadership experience guidelines determined by the U.S. Department of Education (DOE) for this program. Individual interviews were used to obtain the perceptions of teacher leaders. Data were collected for analysis of practices and behaviors of teacher leaders within a framework of distributed leadership. This study reports on why and how teacher instructional leadership practice choices were made within the experiences of the participants. Findings support the promotion of instructional teacher leadership within a distributed leadership model for sustaining instructional reform initiatives. The study contributes to a more complete picture on how and why teacher leaders engage in their instructional leadership behaviors (Kenjarski, 2015, p. 182, Spillane, 2015). Recommendations for sustaining teacher leader approaches in school distributed leadership configurations are included. [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.]