Cassia angustifolia, a plant which has been extensively used in traditional medicine, was explored for its total antioxidant and total antimicrobial activities. The leaf extract was prepared using maceration and the Soxhlet extraction method with hexane, chloroform, ethyl acetate, and methanol solvents, which are non-polar and polar solvents, respectively. In the present study, DPPH, ABTS, and FRAP assays at 20, 40, 60, 80, 100, 150, and 200 μg/mL concentrations exhibited a substantial free radical-scavenging activity in terms of the calculated IC₅₀ values. The extract was further tested against four bacterial pathogenic species, namely, Escherichia coli, Bacillus subtilis, Staphylococcus aureus, and Klebsiella pneumoniae, using the agar well diffusion method, resulting in impressive proved zones of inhibition. The extract's antifungal effect was evaluated against Candida albicans, Aspergillus niger, Aspergillus flavus, and Aspergillus fumigatus, and the extract showed great inhibition of fungal growth, indicating that the plant has high-spectrum antimicrobial activity. This study shows that C. angustifolia leaf extract has very high antioxidant potential activity, thus helping to combat oxidative stress. It also has the potential for broad-spectrum antimicrobial activity. Our results also suggest that the extract could be useful in the pharmaceutical, agricultural, food, and cosmetic industries, as the findings point to the fact that it is a natural source of antioxidant and antimicrobial substances. To establish and define its therapeutic use and identify its active compounds, more research is required in the future. Our findings will aid in future medicine and drug discovery, as well as in the exploration of the casia species and their medicinal properties.