Metal hollow spheres (MHS) and metal hollow sphere structures are special types of cellular metals with an enormous application potential in structural and functional applications. A lot of effort has been made during the last two decades in order to develop the manufacturing process and to investigate the properties of this type of structure. Additional functionalizing of MHS is possible by filling the spheres with ceramic powders or phase change materials. Furthermore, by coating the spheres with different ceramic layers new properties and functions are added. Thus, the structures show excellent mechanical damping properties as well as high heat capacity for thermal storage and fast heat loading and unloading. Grinding or ceramic coating bring more functions to the surface of the spheres. The manufacture and properties of different types of functionalized MHS and their possible applications are highlighted here.