L-Ornithine plays an important role in cell proliferation, collagen formation, and other physiological functions. It is an excellent nutritional supplement for bodybuilders and sportsmen. Because of its several functions in health care, l-ornithine has a substantial global market; thus, a simple, efficient, and energy-saving technique for producing l-ornithine is required. Currently, several studies exploit arginase as an efficient catalyst for the sustainable synthesis of L-ornithine. Arginase cleaves L-arginine to form L-ornithine and urea and acts as a committed step in the urea cycle. It was also studied as an arginine-reducing agent to treat arginase deficiency and to treat arginine auxotrophic tumors. Many studies have been reported for the production of L-ornithine by microbial arginases, but the isolation of arginase from low-cost materials like plant biomass is still a field of study. This review focuses on the production of arginase from potent microbial strains for the cost-effective production of ornithine and the study of its therapeutic applications and emphasizes the development of robust microbial strains with high stability and productivity.