Aegle marmelos, a well-known Indian plant with medicinal and religious importance, has been extensively used in Indian traditional medicine. The present study aimed to isolate, identify, and evaluate the biological activities of endophytic fungi from A. marmelos. One of the isolates, labeled as L7, was identified as Aspergillus flavus using morphology and ITS gene sequence. Total phenolic and flavonoid contents in the culture filtrate were found to be 65.77 mg GAE/ml and 158.33 mg quercetin/ml of crude extract, respectively. The extract showed excellent antimicrobial activity against common human bacterial and fungal pathogens. The test extract at 700 A mu g/ml, which notably reduced the concentration of DPPH-free radical as percent DPPH scavenging activity, was found to be the highest (64.53 %). The extract, at the concentration of 2 mg/ml, produced 70 % inhibition of hemolysis of RBCs compared to 78 % produced by standard drug (Ibuprofen). Chemical profiling of the fermented extract using TLC followed by UV and FTIR revealed the presence of flavonoids. The HPLC analysis confirmed the presence of bioflavonoid rutin in the extract. To the best of our knowledge, this is the first report on production of bioactive flavonoid by endophytic Aspergillus flavus obtained from A. marmelos and its pharmaceutical potential. In conclusion, the endophytic Aspergillus flavus obtained from the A. marmelos could be explored as an economic and potential natural resource with diverse pharmaceutical and biological activities.