[1][5] In the West Atlantic it ranges from Virginia (occasionally Cape Cod) to northern Argentina, including the Caribbean Sea and Gulf of Mexico.

[1] Widespread in the Indo-Pacific region, ranging from the Red Sea to South Africa, Japan, the entire coast of Australia (except Tasmania and Victoria) and Fiji, they are absent from the central Pacific Ocean, including Hawaii.

[1] The largehead hairtail prefers relatively shallow coastal regions over muddy bottoms,[1] but it sometimes enters estuaries and has been recorded at depths of 0 to 589 m (0–1,932 ft).

[11][12] Morphometric and meristic differences have also been shown in the population of the East Pacific (California to Peru), leading some to recognize it as T.

[1] However, this would require that T. japonicus, T. nitens and the Indo-Pacific populations also are recognized as separate species, effectively limiting T. lepturus to the West Atlantic (contrary to IUCN[1]), as they all show a greater divergence.

Based on studies of mtDNA, which however lacked any samples from the southern parts of the Pacific and Indian Oceans, there are three species in the Indo-Pacific: T. japonicus (marginal in the region, see range above), T. lepturus (West Pacific and Eastern Indian Ocean; the species also found in the Atlantic) and the final preliminarily referred to as Trichiurus sp.

[17] The names T. coxii and T. haumela have been used for the populations off Australia and in the Indo-Pacific, respectively, but firm evidence supporting their validity as species is lacking.

[12][15] Juveniles participate in the diel vertical migration, rising to feed on krill and small fish during the night and returning to the sea bed in the day.

[2][3] Other known prey items include squid and shrimp, and the highly carnivorous adults regularly cannibalise younger individuals.

[1] In 2009, by far the largest catches (1.2 million tonnes) were reported by China and Taiwan from the Northwest Pacific (FAO Fishing Area 61).

[22] Some of the numerous other countries where regularly caught include Angola, Nigeria, Senegal, Mauritania, Morocco, Brazil, Trinidad, Colombia, Mexico, southeastern United States, Iran,[1] India,[19] and Australia.

[4]In Korea, the largehead hairtail is called galchi (갈치), in which gal (갈) came from Middle Korean galh (갏) meaning "sword" and -chi (치) is a suffix for "fish".