The availability of elastomers that are resistant to biodiesel, petrodiesel, and their blends can provide a great impetus to the enhanced utilization of biofuels. However, due to the inherent differences in the polarity of biodiesel and petrodiesel, it has been realized that finding a single elastomer compatible with both types of fuels and their blends is extremely difficult. This study reports an approach to circumvent such limitations by modifying the elastomer backbone via grafting of a polymer with markedly different polar and dispersive components of the solubility parameter in the Hansen’s solubility space from either type of fuel. Ethylene propylene diene monomer (EPDM) (δD, δP, δH = 18.6, 3.4, 4.4 MPa1/2) was chosen as the elastomer matrix, and acrylic acid (AA) (δD, δP, δH = 11.3, 8.1, 5.2 MPa1/2) was chosen as the monomer to be grafted. To enhance the grafting yield of AA, silica percolated EPDM (SiEP) matrix was developed. This approach led to a significant increase in the grafting yield and fuel resistance; furthermore, the tensile strength increased by several fold while maintaining elongation at break of more than 700%. EPDM rapidly disintegrated in petrodiesel, whereas AA grafted silica percolated EPDM (AA-g-SiEP) maintained its integrity. Notably, even in biodiesel and biodiesel/petrodiesel blends, AA-g-SiEP had lower fuel uptake. These results were explained by considering the preferred orientation of the polar group of biodiesel toward AA domains, forming a barrier layer which impedes the further diffusion of fuel molecules. These observations suggest that the development of graft structures with extremely different matrix–graft solubility parameters can be used for designing materials resistant to chemical environments which have a different or mixed solubility profile.