The microstructures and properties of carbon nanotube (CNT)/metal nanocomposites, which are fabricated by the molecular level mixing process, have been investigated for multifunctional applications as structural and functional materials. The molecular level mixing process provides a homogeneous dispersion of carbon nanotubes in metal matrices by inducing the ionic bonding between functionalized carbon nanotubes and metal ions. For the structural applications, CNT/Cu nanocomposites showed an outstanding enhancement in mechanical properties such as strength, modulus, and wear resistance. For the functional applications, CNT/Co nanocomposites showed excellent field emission behavior for possible applications on next generation field emission displays. SiC/W nanocomposites, fabricated by using CNT/W nanocomposite powders, showed good ablation properties for the applications as rocket propulsion materials.