<p>Addressing the dual challenges of high heat flux dissipation and long-term reliability in advanced electronics, this study presents a novel strategy for fabricating multifunctional thermal interface materials. The approach synergistically integrates magnetic field-induced filler alignment with ultrasonic cutting surface structuring. Carbon fibers (CFs) were incorporated into a conventional Al₂O₃/silicone rubber (SR) system. A high magnetic field was employed to vertically align the CFs, constructing efficient axial pathways for phonon transport. Subsequently, a post-curing ultrasonic cutting process served a dual purpose: exposure of the aligned CF ends and<i> in situ</i> generation of a hierarchical micro/nano-rough structure on the SR matrix. The effects of CF content on the microstructure, through-plane thermal conductivity (TC), and surface wettability were systematically investigated. Results demonstrate that at an optimal SR:CF mass ratio of 1:2, the composite simultaneously achieves an exceptional through-plane TC exceeding 16&#xa0;W/(m·K) and superhydrophobicity, with a water contact angle (CA) &gt; 155° and a sliding angle (SA) &lt; 5°. Microstructural and mechanistic analyses reveal that the magnetically aligned CF array, synergistically bridged by Al₂O₃ particles, forms a continuous three-dimensional (3D) hybrid network that drastically enhances the effective phonon mean free path, responsible for the superior TC. Concurrently, the hierarchical roughness created by ultrasonic cutting, combined with the intrinsic low surface energy of the components, stabilizes the Cassie–Baxter wetting state, yielding robust and intrinsic superhydrophobicity without any post-surface modification. This work provides a new design paradigm and a scalable fabrication route for next-generation thermal interface materials that integrate efficient cooling, self-cleaning, and enhanced environmental durability.</p> Graphical Abstract <p></p>