This study evaluated the techno-functional and structural properties of grass pea (Lathyrus sativus) protein isolate (GPI) across five distinct treatments: Grass Pea Isolate (GPI),, heat-treated GPI (HGPI), HGPI with xanthan gum (HGPI+XG), microparticulated HGPI (HGPI+MPs), and a microparticle-xanthan gum complex (HGPI+MPs+XG). Alkaline extraction yielded a high-purity isolate (91.27%). Although thermal treatment induced protein denaturation leading to undesirable macro-aggregation, incorporating xanthan gum during high-shear microparticulation effectively prevented particle coalescence via protein-polysaccharide interactions, boosting microparticle yield to 92.03%. Structural modification and partial chain unfolding established an optimized 3D macromolecular network, reducing the least gelation concentration (LGC) to 8%. The HGPI+MPs+XG complex exhibited superior performance, with notable increases in pH-dependent solubility, emulsifying capacity, emulsion stability, water-holding capacity (WHC, 82.76% to 98.49%), and oil-holding capacity (OHC, +97.77%). Fluorescence microscopy, PDIDLS (0.07 μm), Sutter number (5.91 μm), and DPI (1.06 μm) observations confirmed the formation of spherical, homogeneous, and stable microparticles. Disulfide bond analysis indicated that sulfhydryl groups were directly involved in driving this structural stability. Overall, these findings indicate that microparticulated grass pea protein complexes hold significant potential as texturizing and emulsifying agents for clean-label food formulations and potential application in plant-based matrices, pending further sensory evaluation, texture profile analysis (TPA), and real-food matrix stability studies.