Hierarchical channel structures are an ubiquitous motive in nature and play a vital role in the design of complex functional matter as well as in the efficient transport and distribution of resources. Inspired by nature, we demonstrate a scalable concept for incorporating a functional hierarchical microchannel system into a soft polymer matrix based on polydimethylsiloxane (PDMS) without the need for any cleanroom processes. The concept is based on a ceramic template consisting of tetrapodal-shaped zinc oxide microparticles, that can be tailored in porosity (between 50% to 98%), size (up to several cm³) and geometry. By filling the porous volume of the template with PDMS, followed by the wet-chemical removal of the sacrificial template, an interpentraing network of microchannels remains within the polymer matrix. Previously, it has been demonstrated that these composites can be used as a membrane, through which the substance transport can be tailored precisely by varying the microchannel density. Here we show, that (1) functionalizing the microchannels with a thin film of graphene nanoflakes and (2) filling the microchannel networks with stimuli-responsive materials, enables the fabrication of functional interpenetrating composite materials. The obtained composites can be tuned in their physical and electrically-controlled in their mechanical properties. Furthermore, the template-based approach enables the fabrication of structures with heterogeneous volume properties, for example by varying the microchannel locally, allowing for even further complex functionalities.