<p>Fossil fuel-based materials have hazardous effects on humans, animals and entire ecosystems. Current environmental concerns arising from such effects have motivated the search for polymers of renewable origin. Chitosan, a known name among biopolymers of significant interest to research investigations is the most abundant natural amino polysaccharide. Due to its characteristics of biocompatibility, biodegradability, non-toxicity, antimicrobial ability, low cost of production, ease of modification and renewability is a promising alternative to fossil fuel-based materials. Chitosan is commercially produced by the deacetylation of chitin and comprises of 44.11% carbon, 6.84% hydrogen and 7.97% nitrogen. Its biological properties are determined mainly by its molecular weight and the degree of deacetylation (DD), so that the higher the DD, the better the properties. Moreover, the source of chitosan as well as other factors occurring during the manufacturing process can influence the physicochemical qualities and cause variations in the final product. Commercially available chitosan has an average molecular weight ranging from 3800 to 20,000 daltons. Chitosan is a distinctive liner polycation consisting of reactive amino and hydroxyl groups, a high charge density and an excess of hydrogen bonding. The presence of reactive functional groups on chitosan provides an ample range of derivatives such as carboxyalkyl, sugar-bearing, N-trimethyl, cyclodextrin-linked and thiolated chitosan. The amino acid group particularly gives chitosan its positive charge as well as makes it easily dissolvable in aqueous acidic solutions. The biopolymer is however poorly soluble in water and hence requires modification to enhance its aqueous solubility and increase its applicability across domains. This paper synthesizes existing research to provide a comprehensive review of chitosan. It discusses the traditional and biotechnological (enzymatic and microbial) methods of chitosan production, its applications in the biomedical industry for; wound healing, tissue engineering and target drug delivery, in the agricultural industry for enhancing soil fertility, plant growth stimulation, mitigation of post-harvest diseases and induction of plant defense system against phytopathogens, in environmental care for wastewater treatment, as well as in the food industry for food preservation. Recent advancements in nanotechnology, bioelectronics, and environmental sustainability have also been discussed.</p>