Materials scientists always dream to ‘paint’ nanostructured metal on a metallic foil, just as artists paint a painting on a canvas. Herein, we have, for the first time, realized this dream using liquid gallium (Ga) as the paint. Through a liquid Ga stimulated painting–alloying–dealloying strategy, seven kinds of nanostructured metallic films including Au, Ag, Pd, Pt, Cu, Co, and Ni were generally fabricated and supported on the corresponding metallic foils. Owing to the painting-like operation, nanostructured films with complicated patterns and large sizes (up to meters) were successfully produced without any shape/size limitations. The nanostructured metallic films possess advantages like their unique nanoporous structures, self-supporting nature, good continuity, flexibility and high specific surface areas, and could serve as robust electrodes in devices like batteries, fuel cells, water splitting electrolyzers, etc. Moreover, the proposed strategy shows great potential in the fabrication of other self-supporting, flexible, advanced nanomaterials.