Abstract: Butyrate is a short-chain fatty acid of four carbons in length that is a by-product produced by the microbial fermentation of dietary fiber and undigested carbohydrates within the colon. Over the years, butyrate has attracted significant attention due to its diverse roles within cells. These roles include that it serves as an energy source, regulates histone deacetylation, impacts cell development, influences various cellular processes such as apoptosis and autophagy, exerts immunomodulatory functions, and maintains intestinal barrier integrity. Recent studies indicate that butyrate also plays a major role in brain function by strengthening the integrity of blood–brain barrier (BBB), can cross the BBB to exert beneficial effects including modulation of neuroinflammation and neurotransmitter secretion, while acting as a key signal carrier molecule to improve bi-directional communication between the gut and the brain via the gut–brain axis. This perspective aims to summarise butyrate’s intricate cellular mechanisms and their effects on overall health, including neurological well-being.