Abstract: Under the strategies of Building a Leading Sporting Nation and Healthy China, with digital technologies deeply embedded in the public service system, balancing efficiency improvement with equitable access has become a key issue. However, existing research has yet to systematically address whether new digital infrastructure can enhance the efficiency of public fitness services, through what mechanisms, and how it affects equalization. Based on provincial panel data from 30 provincial-level administrative regions in China, this study employs a two-way fixed effects model for empirical analysis and finds that: 1) New digital infrastructure significantly enhances the efficiency of public fitness services—a one-unit increase in digital infrastructure level is associated with an approximate 0.025-unit increase in the efficiency index (equivalent to 15.4% of the sample mean), and this conclusion remains robust after multiple robustness checks. 2) The effectiveness of the new digital infrastructure in enhancing the efficiency of public fitness services shows significant heterogeneity: In terms of the spatial dimension, the western region is the most statistically significant, while the eastern region benefits slightly but significantly, and the central and northeastern regions do not show significant benefits; in terms of the demographical dimension, regions with a higher degree of aging benefit more significantly, while regions with a lower degree of aging do not show any obvious effect. 3) From the perspective of the influencing mechanism, the new digital infrastructure mainly enhances the efficiency of public fitness services through the two paths of increasing the number of sports high-tech enterprises and increasing the attention to artificial intelligence. 4) Further analysis reveals that the new digital infrastructure not only accelerates the overall improvement of the efficiency of public fitness services, but may also exacerbate the imbalance in regional development in the short term. This paper deepens the understanding of the application of the TOE framework in the field of public fitness services, identifies the transmission path through which the new digital infrastructure affects efficiency by the number of high-tech enterprises and the attention to artificial intelligence, and reveals its non-equilibrium impact on regional equality. Accordingly, it provides policy implications for digital infrastructure empowering public services: an effective transformation from technological empowerment to efficiency output should be achieved by expanding facility coverage, fostering innovative entities, and strengthening technological demonstrations.