Extracted and purified hemicelluloses from different plant sources were reported to be suitable crosslinkers in the synthesis of polymeric networks, such as hydrogels. These hydrogels were reported to have a possible medical application or to be part of water purification set-ups. To make these different applications possible, the produced hydrogels need to have specific chemical and physical properties. One way to tailor the final characteristics of the hydrogels is the defined modification of the hemicelluloses in order to generate highly effective hemicellulose-based crosslinkers. In this work, the synthesis of Omicron-acetyl galactoglucomannan derivatives bearing methacrylic functional groups were studied and the produced crosslinkers were applied in the synthesis of various hydrogels with various swelling degrees. In order to improve the mechanical strength of the hydrogels, the application of softwood or hardwood nanofibrillated cellulose (NFC) as a reinforcement material in the cationic hydrogels was studied. Fourier Transform Infrared spectroscopy (FTIR), nuclear magnetic resonance spectroscopy (NMR), and scanning electron microscopy (SEM) and static compression measurements were applied to characterize the GGM derivatives and the GGM-based hydrogels. The GGM-based hydrogels were tested in respect to their capacity to remove chromate ions from aqueous solutions and the obtained results underline the high potential of such biocomposites.