The current study aimed to explore the phytochemicals, estimate the anti-inflammatory, antioxidant, antimicrobial, and anticancer potentials of polyphenol enriched methanolic bark extract of Grewia asiatica (PEMGa), and perform molecular docking studies with identified phytocompounds. Here, we utilized response surface methodology (RSM) with a Box Behnken design (BBD) to enhance the phenolic content of the methanolic extract from G. asiatica bark by optimizing three crucial parameters like extraction time (h), temperature of extraction (°C), and solvent ratio (% v/v of methanol: water). Phytochemical quantification of PEMGa illustrated that the bark part contains a good amount of therapeutically potent phytochemical groups like phenolics, flavonoids, and tannins. Additionally, through HPLC analysis, eight compounds belonging to the phenolic and flavonoid groups have been quantified from PEMGa. By GC-MS (Gas chromatography–mass spectrometry) analysis of PEMGa, eleven phytochemicals were identified. Moreover, employing in-vitro bioactivity studies, PEMGa has unveiled its remarkable potential as an anti-inflammatory, antimicrobial, antioxidant, and anticancer agent. During the in-silico molecular docking study, out of eleven phytocompounds identified by the GC-MS study, three compounds, namely, γ-sitosterol, stigmasterol, and campesterol, formed the most stable docked complex with anti-inflammatory, antimicrobial, and antioxidant target proteins. The present study provides justification for the bark part of G. asiatica as a rich source of potent phytochemicals, and its potential against oxidative stresses, inflammations, cancer, and microbial infections.