Although researchers have identified a number of instructional strategies as evidence-based, teachers often do not employ these practices sufficiently, perpetuating a research-to-practice gap. Traditional professional development is often insufficient to change teacher practice, resulting in a need for specific, supplemental interventions. Performance feedback is one such method that has a growing evidence base. However, while feedback has been demonstrated to be most effective when delivered immediately, performance feedback is often provided to teachers on a deferred schedule (e.g., the next day). In this preliminary investigation with one middle school mathematics teacher, we used a withdrawal design to evaluate a method for delivering visual performance feedback (VPF) in real-time using commonly available technology. Results demonstrated that the teacher's overall frequency of positive feedback increased following VPF delivery, with positive collateral effects on student behavior. Findings suggest the intervention warrants further study; implications for practice and future research are discussed.