Herein, we report a general and template-free protocol to construct novel yolk–shell metal@carbon nanospheres based on confined interfacial copolymerization, which greatly simplifies the synthetic route, yields uniform nanospheres with controllable diameters, and results in highly porous carbon shells. The yolk–shell Au@carbon shows improved adsorption capacity and high catalytic ability due to the synergistic effect of Au and the porous carbon shell.