This work reports on the characterization of a novel protein-based plastic synthesized from bovine serum albumin (BSA) using Subcritical water technology. In the present study, the mechanical and thermal properties of the novel plastic (PBSA) are presented while investigating the effects of blending biodegradable organic compounds on its mechanical properties. The average ultimate tensile strength (UTS) of the processed PBSA samples was 12.7 MPa with a modulus of elasticity (E) and tensile strain at the break (6) of 370 MPa and 1.7%, respectively. Blending 10% glycerin with PBSA resulted in a reduction in the UTS (10.1 MPa) but increased the E value (4.4%). An increase of the glycerin percent to 25% further decreases the UTS (8 MPa) while further increasing c (7.8%). The addition of 10% starch resulted in a reduction in both the UTS and E (7.3 MPa, 1.3%). Conversely, the PBSA with 25% starch blends showed a dramatic reduction in UTS (0.6 MPa) while increasing the E value (2.8%). A scanning electron microscope (SEM) was used to investigate the morphological properties of the tested samples. The SEM images showed a smooth and homogeneous morphology in the glycerin blend and a phase separation in the starch blend.