Laser Powder Bed Fusion (L-PBF) is an advanced additive manufacturing (AM) technique widely used for producing complex metal components with high precision and flexibility enables the development of new alloys and metal matrix. AISI 316L stainless steel, commonly employed in L-PBF, is known for its excellent corrosion resistance and ductility, However, its relatively low hardness and limited wear resistance present significant limitations in more demanding applications. To address these challenges, this study investigates the use of hexagonal boron nitride (BN) as a reinforcing phase to modify the microstructure and improve the mechanical properties of L-PBF AISI 316L parts. Microstructural characterization through optical microscopy (OM) and scanning electron microscopy (SEM) revealed distinct modifications in grain morphology, and the presence of solidification cracks, primarily attributed to the rapid cooling inherent to the LPBF process. X-ray diffraction (XRD) identified phase composition and secondary phases, while x-ray computed tomography (XCT) assessed internal porosity and subsurface defects in the fabricated parts. The mechanical results demonstrate that incorporating BN into L-PBF AISI 316L leads to a substantial improvement in performance. Nanoindentation hardness increased from 5.01 GPa to approximately 20%, while the microhardness rose from 210 HV by about 15%. These findings highlight that BN reinforcement is an effective strategy for enhancing the strength and durability of L-PBF AISI 316L components.