A fluoroalkyl-silane (FS)-modified three-dimensional (3D) graphene foam (GF) composite (FS-GF) with a hierarchical porous microstructure was fabricated via a nickel foam template chemical vapor deposition and followed modification. The 3D GF, as an electrically conductive framework and hydrophobic porous substrate, was grafted with FS to further improve the hydrophobicity due to its long non-polar molecular chains and numerous fluoric/silicon functional groups. Porous FS-GF with high electrical conductivity (similar to 650 S/m) is functionalized as a Joule-heating mesh for airflow, which synchronously demonstrates rapid heating rates, high conversion efficiencies, and uniform temperature distributions. Moreover, FS-GF exhibits self-cleaning and anti-icing properties that are superior to metallic and inorganic coatings. The outstanding performances of FS-GF suggest the potential for functionalizing 3D graphene composites using hierarchical structures at the multi-scale and chemical modifications of functional molecular groups.