The electron field emission properties of multiwall carbon nanotubes (MWCNTs) grown on sulfur-incorporated nanocomposite carbon (n-C:S) buffer layer were investigated. Both the MWCNTs and the n-C:S films were synthesized in a hot filament chemical vapor deposition system at relatively low methane concentrations. The n-C:S buffer layer provides good contact and adhesion to the Mo substrate and good contact and interface to the MWCNTs. The presence of this buffer layer was shown to improve the reproducibility and stability of the field emission behavior of MWCNTs. The turn-on field (EC) varies as much as 1.1 V/μm after high current density operation when there is no buffer layer, but variations up to only 0.3 V/μm are observed when the buffer layer is present. These results are interpreted in terms of the n-C:S buffer layer role, providing good adhesion and contact to the substrate side and to the MWCNTs, hence ensuring a high density of continuous paths for electrons from the substrate to the MWCNTs.