BACKGROUND AND PURPOSE: Postacute care reform is driving physical and occupational therapists in skilled nursing facilities (SNFs) to change how they deliver care to produce better outcomes in less time. However, gaps exist in understanding determinants of practice change, which limits translation of evidence into practice. This study explored what determinants impacted change in care delivery at 2 SNFs that implemented a high-intensity resistance training intervention. METHODS: We used a mixed-methods, sequential explanatory design to explain quantitative findings using qualitative methods with a multiple-case study approach. Quantitative data were collected on therapists attitudes toward evidence-based practice and aspects of intervention implementation. We conducted focus groups with therapists (N = 15) at 2 SNFs, classified as either high- (SNF-H) or low-performing (SNF-L) based on implementation fidelity and sustainability. RESULTS AND DISCUSSION: Determinants of SNF rehabilitation practice change included the organizational system, team dynamics, patient and therapist self-efficacy, perceptions of intervention effectiveness, and ability to overcome preconceived notions. A patient-centered system, positive team dynamics, and ability to overcome preconceived notions fostered practice change at SNF-H. While self-efficacy and perception of effectiveness positively impacted change in practice at both SNFs, these determinants were not enough to overcome challenges at SNF-L. To adapt to changes and sustain rehabilitation value, further research must identify the combination of determinants that promote application of evidence-based practice. CONCLUSIONS: This study is the first step in understanding what drives change in SNF rehabilitation practice. As SNF rehabilitation continues to face changes in health care delivery and reimbursement, therapists will need to adapt, by changing practice patterns and adopting evidence-based approaches, to demonstrate value in postacute care.