The high power density and intelligence of next-generation flexible electronic devices bring many challenges to fabricate flexible composite films with electromagnetic interference (EMI) shielding effectiveness (SE) property and excellent toughness via a simple method. Herein, inspired by the layered structure and biopolymer matrix networks in natural nacre, nacre-like layered Ti₃C₂T_X (MXene)/aramid nanofiber (ANF) films were fabricated through sol-gel, vacuum-assisted filtration, and hot-pressing. Three-dimensional (3D) interconnected aramid nanofibers networks between adjacent layered MXene result in an ultralong strain-to-failure of the film. Even though the functional filler MXene contents are as high as 60 wt.% and 70 wt.%, the strain-to-failure of the films could reach astonishing values of 18.34% ± 1.86% and 14.43% ± 1.26%, respectively. And the tensile strength could maintain about 85 MPa. Excitingly, with such a high filler, the film can also withstand double folding and vigorous rubbing without damage, which could better adapt to a harsh application environment. The result means that this work provides a convenient way to prepare other high functional filler composite films with excellent mechanical performance. The EMI SE values could reach 45 and 52.15 dB at 60 wt.% and 70 wt.% MXene in 8.2–12.4 GHz. Meanwhile, the films have prominent Joule heating properties, high sensitivity (< 15 s), small voltage operation (0.5 V), and high operation constancy (1300 s). Therefore, nacre-inspired MXene/ANF composite films in this work have ability to apply in many areas including communication technology, military, and aerospace.