This study was conducted to evaluate the contributions of fat addition levels and storage duration at -18 °C to the oxidation and physicochemical changes of frozen pork dumpling filler. With an increase in the fat addition, thiobarbituric acid-reactive substances and carbonyl production increased (P < 0.05), the transition temperatures (Tmax) shifted to lower temperatures, and the total enthalpy (ΔH) of protein denaturation reduced (P < 0.05). Dynamic rheological measurements revealed a compromised viscoelastic network in filler protein gels with increased fat levels and storage time. Increasing the fat level also increased cooking loss and decreased breaking strength (P < 0.05). The sensory results showed that the dumplings with a high fat level had significantly higher texture, juiciness, and overall acceptability scores (P < 0.05). The results suggest that the dumplings with a high fat level stored for long periods enhanced oxidation and cooking loss and decreased breaking strength; however, it is important to add proper fat considering the palatability.