The increasing disposal of emerging contaminants in the environment is a worldwide concern due to environmental impacts, such as toxicity, hormonal disorders, and bioaccumulation. The persistence of these pollutants in water bodies makes conventional pollutant removal techniques inefficient or partial, thus requiring the development of new, more effective, sustainable remediation technologies. Therefore, chitosan-based materials have emerged as a promising alternative for application in catalysis and contaminant removal. The biopolymer has functional properties that make it an excellent adsorbent capable of removing more specific pollutants, such as pharmaceuticals, microplastics, agricultural pesticides, and perfluoroalkyl and poly-fluoroalkyl substances, which are increasingly in evidence today. Therefore, this review of recent and advanced research into using chitosan to manufacture catalytic and adsorption materials offers an innovative approach to treating contaminants in aqueous environments, significantly reducing their presence and impact. It discusses the advantages of using chitosan as an adsorbent and catalyst and its role as a support for catalysts and biocatalysts. In addition, the review highlights the diversity of the physical forms of chitosan, such as particles, membranes, and hydrogels, and its possible chemical modifications, highlighting its effectiveness in catalytic applications and the removal of a wide range of emerging contaminants.