Bacteriophage (phage) therapy is an emerging adjunctive strategy for treatment-resistant periprosthetic joint infections (PJI), but evidence on long-term outcomes and criteria for sustained control of infection remains limited. We previously reported the first use of personalized phage therapy in Canada for a life-threatening, multidrug-resistant (MDR) Staphylococcus epidermidis PJI. Here, we report longer-term clinical and microbiological follow up over two years, demonstrating sustained clinical control of infection with microbiological evidence of no recurrence. This study provides longitudinal clinical and microbiological evidence supporting sustained control of infection following phage therapy, and highlights the importance of standardized clinical and microbiological outcomes to define long-term response to treatment. We propose standardized endpoints for assessing phage therapy in PJI.