Selective laser melting (SLM) is used to fabricate patient-specific, highly precise, accurate dental crown/bridges of Co-Cr-based alloy. However, the quick heating and cooling of SLM-produced parts developed significant quantities of residual stresses, which adversely affected mechanical properties. This study focuses on microwave heat treatment, in order to achieve uniform temperature distribution throughout the material, to maximize the mechanical and microstructural properties, and to reduce power consumption. A comparative study has been performed to investigate the mechanical and microstructural behavior of SLM-printed parts of conventional and microwave heat treatment. The mechanical and microstructural characterization has been performed using micro-hardness and field emission scanning electron microscopy (FESEM), respectively. Additionally, density and surface characteristics have also been analyzed for microwave post-processed and their counterparts. It has been found that heat treatment showed a significant improvement in mechanical and microstructural properties. The refined grain structure has been observed in microwave heat-treated parts as compared to their counterparts. The uniform heating throughout the material can be the reason for enhancing fine-grain structure of Co-Cr alloy. The present study's outcomes can contribute toward the step of cost-effective and sustainable microwave heat treatment of additively manufactured parts.