In this study, we optimized the melt polycondensation of 10-hydroxy-2-decenoic acid (10-HDA) to produce poly(10-hydroxy-2-decenoate) (PHDA) and used it to form crosslinked polyester films of PHDA via thermal- or photocuring. The physical properties of PHDA depended greatly on the polymerization conditions, particularly the temperature. The reaction conditions were optimized to achieve polymers with high weight- and number-average molecular weights of 4.182 × 104 (±0.324%) and 1.588 × 104 (±1.737%) Da. Structural, thermomechanical, and mechanical characterization revealed that the crosslinked polyester films exhibited comparable tensile properties to existing biobased plastics, with a maximum tensile strength of 29.3 MPa and an elongation at break of 331.0%. The films also demonstrated excellent thermal stability, making PHDA a promising alternative to traditional petrochemically derived polymers.