In this study thermoplastic polyurethane (TPU) nanocomposites containing carbon nanotubes (CNTs) and graphene nanoplatelets (GNPs) up to a filler amount of 0.1 wt% were prepared via melt blending and compression molding and the filler dispersion was optimized in order to maximize the mechanical and viscoelastic properties of the nanocomposites. Incorporation of the nanofiller may lead to significant improvement in properties due to the physical presence of the reinforcing nanoparticles, however the TPUs may exhibit significant changes in their morphology, including the soft and hard domain size, the nature of domain interface, as well as the distribution of hard segments in the soft segment phase, which in turn alter the material properties. While direct incorporation of CNTs with solid TPU granules proved to be effective in disentangling and dispersing CNTs within the matrix, GNPs were incorporated in the molten polymer in order to avoid filler aggregation occurring prior to melting of the polymer granules. CNT dispersion was further improved using non-covalent surface modification with a specific surfactant via ultrasonication in DI water and subsequent freeze drying prior to melt compounding. Filler dispersion was also significantly improved by combining the two fillers with different geometric shape and aspect ratio to result in GNP-CNT hybrid filler nanocomposites. Synergistic effects were observed in the TPU-GNP-CNT hybrid composites, especially when combining GNP and CNT at a ratio of 6:4, showing higher tensile modulus and strength with respect to the systems incorporating individual CNTs and GNPs at the same overall filler concentration. This improvement was attributed to the interaction between CNTs and GNPs limiting GNP aggregation and bridging adjacent graphene platelets thus forming a more efficient strain network. Hybrid systems also exhibited the highest creep resistance and recovery ability, since the network formed by 1D-CNTs and 2D-GNPs can hinder the movement of TPU chains, leading to a decrease in viscoelastic and viscous deformation. Morphological analysis carried out by scanning electron microscopy (SEM) indicated that the resulting hybrid nanocomposite presented slightly smaller and more homogeneous filler aggregates. The well-dispersed nanofillers also favored higher phase separation in TPU, as indicated by atomic force microscopy (AFM), resulting in a better microstructure able to enhance the load transfer and maximize the mechanical properties.