Soft hydrogels have become an important class of materials for mimicking and interfacing biological soft tissues with potential applications in drug delivery, tissue engineering and bioelectronics. Creative methods for integrating hydrogels with other materials such as organic conductors are highly desired. Here, we describe the single-step electrosynthesis of PEDOT/alginate into core-shell hybrid structures via an electrochemical-chemical-chemical mechanism. Using a pulsed electropolymerisation protocol, we generated PEDOT in either oxidized or reduced form. By-products of this electrochemical step trigger the chemical reactions for the concomitant assembly of alginate hydrogels. Characterization evidences that PEDOT (core) and alginate (shell) compartments form an electrochemically integrated interface. During growth, both can be loaded with useful cargo. We loaded a negatively charged small molecule and investigated passive and electroactive release mechanisms from the two compartments. Our electro-assisted assembly/crosslinking of integrated PEDOT/alginate hybrids contributes a promising approach to the design of functional interfaces for applications in controlled release and soft electronics.