Capillary and microfluidic chip electrophoresis technologies are heavily utilized for development, characterization, release, and stability testing of biopharmaceuticals. Within the biopharmaceutical industry, CE-SDS and M-CGE are commonly used for purity determination by separation and quantitation of size-based variants. M-CGE is used primarily as an R&D tool for product and process development, while cGMP release and stability testing applications are commonly reserved for CE-SDS. This paper describes the establishment of an M-CGE platform method to be used for R&D and cGMP applications, including release and stability testing, for monoclonal antibodies. The M-CGE platform method enables testing for product development support and cGMP release and stability using the same method, and utilization of one CE technology for the entire lifecycle of a biopharmaceutical product. Critical method parameters were identified, and the analytical design space of those critical parameters was defined using design of experiments (DOE) studies. Once defined through DOE studies, the method design space was validated according to ICH Q2 (R1) guidelines. Additional molecules of the same validated class were verified for use in the method by experimental confirmation of accuracy, specificity, and stability indicating capabilities. The platform method model facilitates rapid utilization of the method in development and GMP testing environments, and eliminates the need for individual validations for assets of the same class entering early stage development.