Cellulose nanocrystals (CNCs) have emerged as fillers of interest to the polymer nanocomposite community due to their inherent properties and renewable precursors. However, challenges persist to incorporate CNCs into polymer matrices due to component incompatibility and/or thermal stability limitations of the nanoparticles. Therefore, the objective of this research is to examine the efficacy of different processing methods in producing CNC/polymer composites. In this work, CNCs were incorporated into polyethylene-co-vinyl alcohol (EVOH) using either a solution casting method or a multi-step method involving the same solution casting method followed by a melt mixing step. The resulting neat EVOH and composite materials were characterized to understand how the viscoelastic character and mechanical properties were influenced by CNC loading and processing method. The results of characterization experiments and micromechanical modeling suggested that the nanoparticle networks produced by each method were different and that a combined solution-melt processing method is beneficial in producing composites with improved properties, particularly at higher CNC loadings. This processing strategy may be more broadly applied to other nanocomposites.