The electron migration polarization is considered as a promising approach to optimize electromagnetic waves (EMW) dissipation. However, it is still difficult to realize well‐controlled electron migration and elucidate the related EMW loss mechanisms for current researches. Herein, we explored a novel FexN@NGC/Ce system to construct an effective electron migration model based on the electron leaps among the 4f/5d/6s orbitals of Ce ions. In Fe4N@NGC/CeSA+Cs+NPs, Ce single‐atoms (SA) mainly represent +3 valence state, which can feed the electrons to Ce4+ of clusters (Cs) and CeO2 nanoparticles (NPs) through conductive network under EMW, leading to the electron migration polarization. Such electron migration loss combined with excellent magnetic loss provided by Fe4N core, results in the optimal EMW attenuation performance with a minimum reflection loss exceeded −85.1 dB and a broadened absorption bandwidth up to 7.5 GHz at 1.5 mm. This study clarifies the in‐depth relationship between electron migration polarization and EMW dissipation, providing profound insights in developing well‐coordinated magnetic‐dielectric nanocomposites for EMW absorption engineering.This article is protected by copyright. All rights reserved