L-methionine is an essential amino acid with a wide range of applications in food, feed, cosmetics and pharmaceuticals. Currently, L-methionine is the only essential amino acid that cannot be industrially produced by microbial fermentation. In recent years, the use of metabolic engineering to enhance the yield of L-methionine has received widespread attention from researchers at home and abroad. In this paper, the biosynthetic pathway and regulatory mechanism of L-methionine in Corynebacterium glutamicum and Escherichia coli are analysed; three key steps (i.e., acylation, sulfurylation, and methylation) in the biosynthesis of methionine from hyper-serine are highlighted, and a further outlook on the biosynthesis of L-methionine is proposed with a view to providing guidance for the industrial production of L-methionine.