Physical activity levels during skilled nursing facility (SNF) rehabilitation fall far below what is needed for successful community living and to prevent adverse events. This feasibility study’s purpose was to evaluate the feasibility, acceptability, and preliminary effectiveness of an intervention designed to improve physical activity in patients admitted to SNFs for short-term rehabilitation. High-Intensity Rehabilitation plus Mobility combined a high-intensity (i.e., high weight, low repetition), progressive (increasing in difficulty over time), and functional resistance rehabilitation intervention with a behavioral economics-based physical activity program. The behavioral economics component included five mobility sessions/week with structured goal setting, gamification, and loss aversion (the idea that people are more likely to change a behavior in response to a potential loss over a potential gain). SNF physical therapists, occupational therapists, and a mobility coach implemented the High-Intensity Rehabilitation plus Mobility protocol with older Veterans (n = 18) from a single SNF. Participants demonstrated high adherence to the mobility protocol and were highly satisfied with their rehabilitation. Treatment fidelity scores for clinicians were ≥95%. We did not observe a hypothesized 40% improvement in step counts or time spent upright. However, High-Intensity Rehabilitation plus Mobility participants made clinically important improvements in short physical performance battery scores and gait speed from admission to discharge that were qualitatively similar to or slightly higher than historical cohorts from the same SNF that had received usual care or high-intensity rehabilitation alone. These results suggest a structured physical activity program can be feasibly combined with high-intensity rehabilitation for SNF residents following a hospital stay.