The manufacture of materials with bulk volumes and precisely controlled nanostructure has led to the creation of materials with surprising and useful mechanical and electrical properties. Recently we have developed a ‘top-down’ fabrication technique that allows the creation of highly-structured multilayer metallic materials, with precisely designed characteristic lengths in the hundreds of nanometers scale, but volumes of manufactured material in the macro range. The fabrication relies on automated and repeated multilayer electrodeposition of multiple metallic materials, followed by sacrificial etching of one metal. The resultant structure consists of individualized high-lateral-aspect-ratio sub-micron metallic films. The application of these multiscale materials to ultracompact energy conversion is investigated. Metallic magnetic materials have desirable magnetic properties, including high permeability and high saturation flux density, when compared with their ferrite counterparts. However, eddy current losses preclude their use in many switching converter applications due to the challenge of simultaneously achieving sufficiently thin (100-500 nm) laminations such that eddy currents are suppressed while simultaneously achieving overall material thicknesses (0.1-1 mm) such that substantial power can be handled. Sequential electrodeposition of multiple nanoscale ‘sheets’, or laminations, of magnetic materials such as permalloy and NiFeCo offers an approach to fabricate the desired nanostructured magnetic core. Tests of toroidal inductors with nanolaminated cores showed negligible eddy current loss relative to total core loss even at a peak flux density of 0.5 T and a frequency of 10 MHz. The ability to operate at such high flux levels offers the possibility of dramatically shrinking the physical size of power inductors in energy converters. DC-DC converters with efficiencies of up to 93% and power handling of approximately 40W have been achieved in ultracompact form based on these materials.