This work explores the synthesis of biomass-waste-derived cellulose nanocrystal hydrogel from aloe vera bagasse (AVB) and banana pseudostem (BPS). A wide variety of synthesis parameters such as acid concentration (45 wt.% and 55 wt.%), temperatures in the process of 25, 40, 45 and 50 °C, and reaction times of 30 and 60 min were analyzed during the acid hydrolysis to evaluate changes in the morphology, crystallinity, swelling, degradation temperature, and mechanical properties. The parameters that most influenced the crystallinity were the temperature and reaction time, showing good characteristics such as percentage crystallinity (89.66% for nanocellulose from C₄₅t₃₀T₅₀ up to 97.58% for CNC-BPS C₅₅t₃₀T₅₀), and crystal size (from 23.40 to 68.31 nm), which was worth considering for hydrogel synthesis. Cellulose nanocrystalline hydrogels from both biomass wastes can modify the crystallinity for tailored high-end engineering and biomedical applications, although using BPS obtained the best overall performance; also, properties such as swelling capability at pH = 4 of 225.39% for hydrogel C₅₅t₃₀T₂₅ (H7), porosity (60.77 ± 2.60%) for C₄₅t₆₀T₄₀ (H6), and gel % (86.60 ± 2.62%) for C₅₅t₆₀T₅₀ (H8) were found. The mechanical test revealed a tensile strength at maximum load of 707.67 kPa (hydrogel H6) and 644.17 kPa (hydrogel H8), which are properties conferred by the CNC from BPS. Overall, CNC from BPS is recommended as a reinforcement for hydrogel synthesis due to its good mechanical properties and functionals, making it a promising material for biomedical applications.