<p>Ionic thermoelectric gels based on the Soret effect play an important role in realizing the efficient conversion of thermal and electrical energy, which is crucial for renewable energy utilization and efficient energy management. In this study, chitosan hydrogels were fabricated by complexation of chitosan and various metal ions <i>via</i> a freeze-casting approach for unitization as ionic thermoelectric materials. Various aggregate structures, including loosely fibrous networks, oriented porous structures, and lamellar porous structures, were obtained owing to the different interactions between chitosan and metal ions. As a result of the synergy of both the aggregate structure and intermolecular interaction, the as-prepared chitosan hydrogels demonstrated wide thermoelectric coefficient ranging from +1.6 mV·K⁻¹ to −18.4 mV·K⁻¹, which can be achieved by simply involving different metal ions. The present work not only demonstrates the correlation between gel structure, intermolecular interactions, and thermoelectric performance, but also provides a simple approach for the fabrication and regulation of natural polymer-based thermoelectric materials.</p>