This article reviews the available literature published to date on the reinforcement of metals with carbon-nanofillers (CNTs and graphene), and also offers a specific focus on issues related to the mechanical and tribological properties of nanocomposites. Carbon-nanofillers (later denoted by C-nanofillers) are known to have extraordinary mechanical properties and multifaceted characteristics and are ideal candidates for the reinforcement of metals for numerous applications. However, their incorporation for practical applications has been challenging researchers for decades. The most important issue is uniform dispersion due to sizeable surface differences between carbon-nanofillers and metals. Other concerns are structural integrity, wetting with metals, and interfacial connections. Nanocomposite applications can only be effective when these challenges are properly addressed and overcome.