Cavity quantum electrodynamics (QED) provides a model system for studying the controlled, coherent coupling of optical and atomic quantum bits. Our research is focused on developing a cavity QED system that couples a nitrogen vacancy (NV) center in a diamond nanostructure to a whispering gallery microresonator. We have developed a composite system that allows for a diamond nanopillar to be precisely positioned near the surface of a microsphere at liquid helium temperatures. When working with NV centers, silica microresonator are the only class of optical cavities with quality factors high enough to operate in the strong coupling regime. The optical stability and instantaneous linewidth of NV centers, created during the growth process or induced via ion implantation, is studied in high-purity single crystal diamond substrates in order to determine their suitability for cavity QED experiments. Concerns regarding the short evanescent field decay length of silica microresonators and the cavity emitter resonance frequency mismatch due to fabrication constraints have been addressed.