Plastic pollution and its detrimental environmental effects have become a global concern. In this study, biodegradable packaging materials were developed by incorporating Tara pod extract (TPE) into soy protein isolate (SPI) films. TPE-SPI films exhibited improved mechanical properties, UV-blocking and heat-sealing performances, and barrier properties. The non-covalent interaction of SPI and Tara tannins enriched in TPE increased the films' tensile strength (TS). At 10% TPE content, the TS of the composite films increased by 56.4%, while the elongation at break (EB) reduced by 26.2%, in comparison to the pure SPI film. With 6% TPE, the composite film efficiently blocked UV lights. The oxygen permeability (OP) of 8TPE-SPI film (0.99 cm3 mm m−2 day−1 atm−1 × 10−9) was significantly lower than that of polyethylene (PE) film (59.5 cm3 mm m−2 day−1 atm−1 × 10−9). At heat-sealing conditions (120 °C, 2.0s, and 0.3Mpa), beef tallow packaged in 8TPE-SPI film showed an increase in POV from 0 to 0.002 g/100 g over 90 days, which was much lower than that of in PE pouches (0.0835 g/100 g). These findings highlight TPE-SPI films have potential to be applied in packaging oily foods.