With the advancement of modern communication technology and military detection technology, there is an urgent need to develop lightweight, flexible, multifunctional composites that integrate efficient infrared (IR) stealth, electromagnetic interference (EMI) shielding, and Joule thermal properties. Nevertheless, the preparation of multifunctional composites with the above properties remains challenging. Herein, multifunctional aerogel films were designed through potassium ionic cross-linking of MXene and aramid nanofiber (ANF), forming an enhanced interpenetrating double-network ANF/MXene-K⁺ (AMK) aerogel. The aerogel film possesses extremely low infrared emissivity (~ 0.097), reducing radiation temperature by more than 89.7% with 9.2 MPa tensile strength. Furthermore, the film exhibits excellent Joule heating performance, including low driving voltage (1.0 V), fast thermal response (< 12.0 s), and long-term stability. Concurrently, the interpenetrating double-network structure of potassium ion-induced self-assembly of MXene nanosheets enabled AMK to demonstrate enhanced electromagnetic shielding (72.4 dB). Overall, this work provides a promising solution for fabricating multifunctional materials and demonstrates their potential in adaptive thermal camouflage systems, next-generation wearable thermal management, and EMI shielding of electronic devices.