Chitosan is an extremely valuable polysaccharide and usually obtained from crustacean byproduct. In this work, a new non-animal source chitosan is obtained from fungal precursors (Ganoderma lucidum spore powders, GLSP) using ultrasound-assisted deacetylation (USAD), and the effects of processing parameters (irradiation time, solid-to-liquid ratio, NaOH concentration, and irradiation power) on the DD (degree of deacetylation) of chitosan were investigated. The highest DD value was obtained at irradiation parameters of 20 min, 10% (g:ml) NaOH, 1:25 (g:ml), and 80 W. In addition, the difference in surface morphology, chemical groups, thermal stability, and crystallinity of the resulting chitosan with the treatment of various irradiation times was examined using the SEM, FTIR, TG, and XRD. The results show a new promising herbal source of edible chitosan and the potential material for biomedical applications. Practical applications: The chitosan obtained from Ganoderma lucidum spore powders (GLSP) possessed many priorities over the chitosan from shells of crustaceans, which involves a multi-faceted procedure with several economical and consumer related aspects. In the current work, chitosan is obtained from an herbal source GLSP using ultrasound treatment and the effect of processing parameters on chitosan was investigated. The findings show the development of chitosan from an herbal source with potential in functional food applications.