The rising demand for convenient, nutritious foods necessitates improved freeze–thaw (F-T) stability in frozen fish balls; however, traditional thermal processing fails to prevent moisture loss, textural degradation, and oxidation. Therefore, this study systematically investigated the effect of ultra-high pressure (UHP) treatment on the quality of golden pomfret fish balls (Trachinotus ovatus) using two-step heating as a control during the F-T cycles. The results showed that compared to two-step heating, UHP significantly reduced the thawing loss (0.68 times) and centrifugal water loss (2.43 times) by enhancing the water-binding capacity (15–20%) and forming denser gel networks. Microstructural analysis revealed that UHP resulted in a more compact internal structure, reduced porosity, altered ice-crystal geometry, and a slower recrystallization rate of the fish balls. Furthermore, UHP effectively reduced protein oxidation (34.53% lower carbonyl increase) and lipid peroxidation (15.6% lower TBARS value) after five F-T cycles compared to the control. Correlation analysis confirmed the dual role of UHP in the regulation of oxidative and structural stability. These findings provide a new technological approach for processing and storing fish balls.