Complex wound closure scenarios necessitate the development of advanced wound dressings that can effectively address the challenges of filling irregularly shaped wounds and managing fatigue failures encountered in daily patient activities. To tackle these issues, we develop a multifunctional hydrogel from natural polysaccharides and polypeptides with injectability and self-healing properties for promoting full-time and multipurpose wound healing. Synthesized through dynamic Schiff base linkages between oxidized hyaluronic acid (OHA), ε-polylysine (ε-PL), and quaternized chitosan (QCS), the OHA/ε-PL/QCS hydrogel can gel rapidly within 50 s. It exhibits notable strong shear-thinning and self-healing behavior, allowing easy injection to fit various wound shapes while maintaining integrity. In rat models of liver and femoral artery injuries, the hydrogel shows significantly reduced bleeding and accelerated hemostasis. The hydrogel can enhance cell proliferation through cell migration and tube formation, stimulate angiogenesis, support collagen deposition, and reduce inflammation. Its superior biocompatibility also supports the safe encapsulation of epidermal growth factor (EGF). In infected full-thickness skin wound models, the OHA/ε-PL/QCS/EGF hydrogel achieves nearly complete wound closure within 10 days. Overall, this study highlights the outstanding therapeutic potentials of the injectable and self-healing OHA/ε-PL/QCS hydrogel as a promising solution for fulfilling the multi-purpose, sophisticated needs in complicated wound closure scenarios.