Alpinia galanga (L.) Willd. (A. galanga) is extremely significant and is utilized extensively in traditional medicine throughout many nations. This study aimed to determine the chemical composition of A. galanga rhizome extract (AgRE) and to evaluate its antioxidant, anticancer, and antibacterial activities. The total phenolic content (TPC) and total flavonoid content (TFC) of AgRE were determined. The antioxidant activity, cytotoxic capability, and antibacterial of were assessed, as well as anti-apoptotic genes. Molecular docking (MD) was used to assess the binding affinity of the most enriched constituents in AgRE toward the active sites of nicotinamide adenine dinucleotide phosphate (NADPH) oxidase and p53 tumor suppressor protein (TP53). Gas chromatography-mass spectrometry (GC-MS) analysis demonstrated that AgRE is a rich source of turmerone. AgRE had moderate 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2,2′-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) radical scavenging properties, with the half-maximal inhibitory concentration (IC50) values of 79.34 ± 1.78 and 88.94 ± 2.28 μg/ml, respectively. AgRE preferentially reduced the viability of a subset of malignant MCF-7 and HepG2 cell lines, with IC50 of 125.35 ± 4.28 and 182.49 ± 3.19 μg/ml, respectively. AgRE exhibited considerable antimicrobial activity against all bacterial strains, with MIC values ranging from 7.81 ± 1.53 to 62.5 ± 3.28 μg/ml. The MD results revealed that ethyl-4-(2-methylpropyl)-benzene had the greatest binding energy with NADPH oxidase, with a Glide score of -6,848 kcal/mol, followed by 2-methoxy-phenol (-5,111 kcal/mol). Taken together, we report the interesting antioxidant, antibacterial, and anticancer properties of AgRE, which warrant further investigation. AgRE is a promising natural resource that could be used to combat complicated diseases such as cancer and bacterial infections.