In response to the growing climate crisis, there is a pressing demand for sustainable and renewable alternatives to traditional petroleum-based resources. One grade of technical lignin, lignosulfonates, has been widely used as a dispersing agent due to its amphiphilic nature. However, the number of mills utilizing the sulfite process, from which lignosulfonates are a byproduct, is declining. To address this challenge, we isolated and characterized oxlignin, a fraction of lignin solubilized during the oxygen delignification stage in kraft pulp production. We employed various analytical techniques, including 31P-NMR spectroscopy, size exclusion chromatography, and thermogravimetric analysis, to characterize oxlignin. The results revealed several notable properties, including its high solubility in water, methanol, and ethanol, as well as its higher concentration of carboxylic acid groups compared to conventional kraft lignins. Our findings highlight oxlignin’s potential as a sustainable and versatile raw material, particularly as a lignosulfonate alternative in dispersing applications. This contributes to ongoing efforts in lignin valorization and offers a path toward enhanced sustainability and resource utilization in bio-based materials.