Tachyplesin II (TP) is a β-folded peptide isolated from horseshoe crabs. TP, with two disulfide bonds, effectively inhibits gram-negative and gram-positive bacteria, fungi and viruses. In this study, the antibacterial and antioxidant properties of synthetic TP were examined. Specifically, TP was incorporated into cross-linked methacrylated gelatine (GelMA) to construct a GelMA-TP hydrogel, which promoted infected wound healing. TP formed intermolecular hydrogen bonds with the GelMA network, endowing the GelMA-TP hydrogel with good antibacterial activity, stable rheological properties, high swelling capacity, self-healing behaviour, and good biocompatibility. We found that the anti-inflammatory and antioxidant activities of the GelMA-TP hydrogel significantly enhanced collagen production, thus accelerating healing in a rat-infected wound model. Overall, the GelMA-TP hydrogel demonstrates significant potential to stimulate the healing of infected wounds by reducing healing time and improving tissue repair outcomes. These findings highlight its translational promise as a clinically effective material for managing complex wounds, particularly in scenarios where conventional therapies are limited by persistent infections or excessive inflammation.