The bar jack is distributed through the western Atlantic Ocean from New Jersey and Bermuda in the north to Venezuela and possibly Brazil in the south, with the largest population in the Gulf of Mexico and West Indies.

The bar jack is a moderately large species, growing to a recorded maximum of 65 cm (26 in) and a weight of 6.8 kg (15 lb).

The species inhabits clear shallow waters, often over coral reefs where it lives either solitarily or in large schools, taking various fishes, crustaceans and cephalopods as prey.

The bar jack was first scientifically described under the name Somber ruber by Marcus Bloch, in 1793 based on a specimen taken from the east coast of America, which was designated to be the holotype.

[6] Caranx is derived from the French word, carangue, or a fish from the Caribbean, while ruber (sometimes incorrectly spelled rubber) is Latin for red.

The lateral line is moderately arched anteriorly, and possesses 17 to 104 scales including 23 to 29 scutes posteriorly; also having bilateral paired caudal keels present.

[11] The bar jack has a gray to grayish blue upper body with a silvery tint, which fades ventrally to a white belly.

As indicated by their common name, adult bar jack have a horizontal stripe running along their back and through the lower lobe of the caudal fin.

[15] The bar jack is widely distributed throughout the tropical and subtropical waters of the western Atlantic Ocean, and is a common species throughout most of its range.

[8] The bar jack generally live in clear shallow water environments, predominantly around coral reefs to depths of around 60 ft (18 m).

[17] Bar jack often venture into lagoons from seaward reefs, preferring to move over the sandy substrate while in these shallow waters, often forming shoals alongside barracudas, stingrays and sharks.

[15] The diet and reproductive biology of the bar jack are relatively well documented, with most studies centered on the waters of Cuba during the 1980s, with nearly all of this research published in the Russian publication Voprosy Ikhtiologii, reprinted in English as the Journal of Ichthyology.

These associations were initiated by both jacks and wrasse, with apparently little pilfering of uncovered items, suggesting a beneficial relationship to both parties.

[20] While foraging with the wrasse, the jack increases its prey detection levels, which is useful for a species which is more adept at pelagic hunting, allowing it to be more efficient at this less common mode of food gathering.

[25] During this early stage of life they are very similar to Carangoides bartholomaei, and often form associations with floating pelagic Sargassum mats which provide the young fish with protection.

Archaeological evidence from San Salvador Island in the Bahamas demonstrates this species has long been targeted by humans for food, with the native Indians of the region often taking the bar jack for consumption, although it was of lesser importance than reef fishes such as parrotfishes and groupers.

[28] The IGFA All Tackle World Record for the species stands at 7 lb 5oz (3.32 kg) jigged up off Martim Vaz Island, Brazil by Fernando de Almeida in May 2012.

[29] The bar jack has a significant risk of carrying the ciguatera toxin in its flesh, and numerous reports of people contracting the poisoning after consuming the fish.