There have been calls for Science, Technology, Engineering and Mathematics (STEM) faculty in higher education to transition from traditional lecturing to instructional practices that are supported by empirical evidence. Administrators can coordinate such transitions through organized change initiatives. At the same time, there has been a shift towards using more fixed-term faculty (instructors) to deliver instruction, especially in large introductory STEM classes. Change initiatives aimed at instigating adoption of evidence-based instructional practices face tensions when balancing the roles, responsibilities, rewards, and acknowledgement of administrators and instructors. In addition, change must be sustained through system-level structures and practices after the formal change initiative ends. This ethnographic study focuses on a change initiative designed to harness distributed expertise of faculty members to lead to the adoption of evidence-based practices. Using the framework of Productive Disciplinary Engagement, we uncover the role of two instructors who became socially enabled actors (SEAs) through developing social connections provided by interactions with the change initiative. Each SEA pursued a personal vision toward effective change in STEM education. Over the three-year study, each SEA's vision became more tangible, more sustained, and more spread. The emergence of these SEAs helped to relieve the tensions between the traditional roles and responsibilities of administrators and instructors by engaging instructors as leaders in STEM education change. In addition, these SEAs maintained authority and developed system-level efforts that could sustain change beyond the ending of the funded project. Importantly, the SEAs' statuses shifted as they were repositioned to become more valued members of the STEM education community doing challenging and important work.