This study investigated the chemical composition (proximate composition, fatty acids, minerals, and phenolic compounds), antioxidant activity, and antimicrobial activity of galangal rhizomes. The rhizomes contain appreciable amounts of ash (5.38%), protein (5.86%), carbohydrate (81.13%), potassium (159.79 mg/kg), calcium (25.7 mg/kg), phosphorous (17.36 mg/kg), magnesium (15.57 mg/kg), iron (7.2 mg/kg) and manganese (3.82 mg/kg). Galangal rhizome oil is rich in unsaturated fatty acids (91.8%), elaidic (67.82%), linoleic (22.56%), palmitic (5.18%), and stearic (2.26%) acids found as the main fatty acids in the oil. Galangal rhizome extract contains substantial amounts of total phenolic content (53.18 mg GAE/g), total flavonoid content (14.12 mg CE/g), gallic acid (160.04 mg/100 g), (+)-catechin (124.33 mg/100 g), quercetin (105.34 mg/100 g), catechol (100.18 mg/100 g), isorhamnetin (82.2 mg/100 g), trans-cinnamic acid (81.97 mg/100 g) and protocatechuic acid (71.46 mg/100 g). The extract of galangal rhizomes also possessed high antioxidant activity, as assessed by DPPH (77.76%), ABTS (8.66 mmol TE/g), and FRAP (3.99 mmol TE/g), as well as antimicrobial activity against ten Gram-positive and Gram-negative pathogenic bacteria. In conclusion, Galangal is a rich source of nutrients and phytochemicals and exhibits antioxidant and antimicrobial activities.