Urban high schools seldom achieve turnaround status. Many variables have been studied in relation to effective school turnaround; however, distributed leadership is a theory of leadership that has seldom been linked in the literature to school turnaround and sustainability. This study investigated the phenomenon of distributed leadership at a southern California urban high school, where indicators revealed that the site achieved turnaround status by moving out of Program Improvement over a ten-year period and by increasing college admission rates, even with multiple principal successions. This study contributes to the field of educational leadership and school improvement by informing how distributed leadership functioned across settings and practices. This unique case study targeted the settings and practices used by multiple stakeholders during the turnaround period. Leadership was characterized by influence and activities, not by roles of site members. Data were collected via in-depth interviews, which were coded by themes of distributed leadership: collegiality, trust, efficacy, autonomy, ownership, collaboration, data-driven design, interaction, teacher talk, emotional support, teacher learning, and a culture of caring. The findings showed that members of a school site took on leadership activities in various settings, influencing one another's' practice. Interview data revealed that teachers, administrators and staff worked in formal and informal settings to influence one another's beliefs and practices. Participants highlighted the importance of conditions that exist when leadership was distributed: ownership, autonomy, trust, and efficacy. These findings suggest that teachers and administrators at urban turnaround schools need to be aware of the differences between formal and informal settings and their effects on distribute leadership practices; by utilizing the unique opportunities each setting offers, learning outcomes for students can be improved and sustained over time.