The present study explores Joha rice-derived starch (JRS) as a multifunctional excipient for pharmaceutical and nutraceutical applications. Starch isolated via the alkaline steeping method was systematically evaluated for its in vivo acute glycemic response, micromeritic properties, compression behaviour (compressibility, compactibility, and tabletability), and dynamic viscoelastic characteristics, in comparison with conventional maize starch (MS). In vivo studies in Wistar rats demonstrated that JRS exhibited a 1.7-fold lower acute glycemic response, with a glycemic index of 42.92 ± 13.41, compared to 73.82 ± 6.10 for MS. JRS also showed a significantly finer particle size (6.18 ± 0.04 µm) than MS (16.4 ± 2.48 µm), contributing to its enhanced compressibility, compactibility, and tabletability. Heckel analysis revealed a lower yield pressure (Py) for JRS (1.23 tons) relative to MS (1.44 tons), indicating superior compressibility. Furthermore, JRS displayed markedly lower lubricant sensitivity (0.04 ± 0.01) than MS (0.23 ± 0.11), ensuring minimal compromise in compact strength and supporting its suitability for direct compression. Notably, dynamic viscoelastic and disintegration assessments confirmed that the swelling (396.57 ± 39.63) and wicking (193.86 ± 1.81) disintegration indices of JRS are comparable to those of MS, demonstrating nearly equivalent disintegration performance.