Carbonaceous nanomaterial-based nanocomposites (CNCs) have recently emerged as an exciting new material platform, exceptional mechanical strength, electrical conductivity, and thermal stability. A range of fabrication methods, such as solution mixing, melt blending, in situ polymerization, and layer-by-layer assembly are discussed in this chapter with respect to advantages, limitations, and applications. These polymer, metal, and ceramic-based composites are used in energy storage, catalysis, biomedical devices, and environmental remediation, as the carbon nanomaterials (graphene, carbon nanotubes, and fullerenes) provide additional functional characteristics. It additionally reflects on critical processing conditions, methods to enhance dispersion and interfacial adhesion, and the impact state-of-the-art synthesis techniques like chemical vapor deposition. Moreover, it highlights the issues of large-scale production, Nanoparticles (NP) agglomeration, and environmental concerns, suggesting possible breakthroughs such as artificial intelligence (AI)-driven material design and green synthesis strategies. Going forward, the evolution of CNCs is going to lie in cost-effective, scalable, and sustainable fabrication methods that can open new avenues for innovation in nanotechnology and advanced material science. This chapter offers a detailed overview on the state-based developments in the field of CNC fabrication and will provide relevant information for the research-based scientists and engineers involving in the area of nanocomposites.