Dielectric elastomers (DEs) have been attracting great attention in the field of electro-mechanical actuation and sensing. In this paper, we develop a new type of silicone-based DEs by incorporating multiwalled carbon nanotubes (MWNTs) to the DEs as fillers. The dispersion of MWNTs during the material processing plays a significant role in deciding the final properties of the nanocomposites. In this work, acetone and ultrasonication along with characterization tools such as scanning electron microscopy (SEM) and transmission electron microscopy (TEM) are utilized to examine the MWNT dispersion quality within DE nanocomposites. Furthermore, microstructural MWNT dispersion and filler–matrix interfacial bonding as well as the overall dynamic mechanical responses are investigated to reveal the correlation between them. It is concluded that the processing of DE nanocomposites strongly affects the dynamic mechanical properties, which can inversely provide with microstructural information for the nanocomposites.