In this study, surface functionalized biochar (Bi) has been examined as a potential alternative to carbon black (HAF) and was used as filler for ethylene-propylene-diene monomer (EPDM) rubber. The influence of surface-treated biochar on the electrical conductivity, oxygen and water permeability, rheological characteristics, and mechanical properties of the elastomer was subsequently assessed in comparison to conventional fillers (HAF) commonly used in rubber applications. The study aims to delineate the key characteristics of the EPDM composites while the effect of the varying ratios of HAF and MBi to elastomers was assessed. Hence, the utilization of environmentally friendly filler extracted from agricultural waste of citrus trees presents a dual advantage: it diminishes the prevalence of citrus tree waste and serves as a sustainable substitute and filler in EPDM to curtail the reliance on common HAF. This strategic incorporation not only contributes to alleviating HAF usage but also elevates the overall quality of rubber-based products, aligning with a commitment to sustainable and eco-conscious manufacturing practices. Moreover, the dielectric spectroscopy and AC-conductivity investigations evidenced that all the obtained composites exhibited an insulator behaviour, which paves the way for a breakthrough in electrical technology.