Eleusine coracana (L.) Gaertn., commonly known as finger millet or ragi, is a food security crop across the arid and semi-arid regions of Sub-Saharan Africa and South Asia. Beyond its long history as a subsistence staple, biomedical research is increasingly documenting its exceptional profile of bioaccessible macro- and micronutrients. This review synthesizes the nutritional, chemical, and pharmacological literature on E. coracana, mapping its phytochemical composition, mineral density, and essential amino acid profile. The crop is unusual among cereal grains for its high calcium concentration (294–390 mg/100 g), a robust complement of sulfur-containing amino acids (particularly methionine and cysteine), and a non-starch polysaccharide network that accounts for up to 20% of total dietary fiber. The seed coat also accumulates substantial polyphenolic content, including hydroxybenzoic acids, hydroxycinnamic acids, condensed tannins, and polymeric flavonoids. We evaluate the mechanisms by which these components address the pathophysiological hallmarks of Type II Diabetes Mellitus (T2DM). Bioactive extracts from E. coracana exert multi-targeted glycemic control through non-competitive inhibition of pancreatic α-amylase and intestinal α-glucosidase, suppression of advanced glycation end-products (AGEs), upregulation of peripheral AMP-activated protein kinase (AMPK) signaling, and modulation of the colonic microbiota that promotes short-chain fatty acid (SCFA) synthesis and reduces low-grade systemic inflammation. Taken together, the evidence supports E. coracana as a viable functional food and nutraceutical candidate for the prevention and management of T2DM-associated metabolic complications.