Applications of metal–ceramic composites are increasing in advanced materials field; however, efficient utilization of these materials depends on the cost involved in processing and structure–properties correlations. Processing of materials through microwave energy has already been accepted as a well-established route for many materials. In this work, composites of nickel-based metallic powder (matrix) and SiC powder (reinforcement) were successfully casted by microwave heating. The mechanism for the development of composite castings using microwaves is discussed with proper illustrations. The results of microstructure analysis of the developed cast revealed that uniform equiaxed grain growth with uniform dispersion of reinforcement. The results of X-ray diffraction analysis revealed that during microwave heating some metallurgical changes took place, which led to higher microhardness of cast. Micowave processed casting revealed lower defects (~1.75% porosity) and average Vickers microhardness of 920 ± 208 HV. This work reports the successful applications of microwaves in manufacturing, in the form of melting and casting of metallic powders.