The abundant transition metal and carbon sources allow imaginative combinations to design porous functional metal–carbon composites for wide applications. However, cumbersome and restricted methods seriously limit the development of mesoporous metal–carbon composites. In this study, a general coordination–polymerization method is reported to construct metal–gallic acid resin, and mesoporous carbon with highly dispersed metal nanoparticles and high metal nanoparticle concentration up to 20 wt%. The metal element composited with polymer and carbon can be various transition metals containing Ti, V, Cr, Mn, Fe, Co, Ni, Cu, and Zn. Furthermore, the general strategy can be expanded to the fabrication of N doped bimetallic catalyst FeCo–MCN-900, which shows comparable electrocatalytic activity and higher stability compared to commercial Pt/C.