Cattle and horses were introduced into Florida in the 16th century. The cattle introduced by the Spanish persist today in two rare breeds: Florida Cracker cattle and Pineywoods cattle. The Florida Cracker Horse, which is still used by some Florida Cowboys, is descended from horses introduced by the Spanish. From shortly after 1565 until the end of the 17th century, cattle ranches owned by Spanish officials and missions operated in northern Florida to supply the Spanish garrison in St. Augustine and markets in Cuba. Raids into Spanish Florida by the Province of Carolina and its Native American allies, which wiped out the native population of Florida, led to the collapse of the Spanish mission and ranching systems.

Though popularly considered American, the traditional Cowboy began with the Spanish tradition, which evolved further in what today is Mexico and the Southwestern United States into the vaquero of northern Mexico and the charro of the Jalisco and Michoacán regions. While most hacendados (ranch owners) were ethnically Spanish criollos, many early vaqueros were Native Americans trained to work for the Spanish missions in caring for the mission herds. Vaqueros went north with livestock. In 1598, Don Juan de Oñate sent an expedition across the Rio Grande into New Mexico, bringing along 7000 head of cattle. From this beginning, vaqueros of mestizo heritage drove cattle from New Mexico and later Texas to Mexico City. Mexican traditions spread both South and North, influencing Equestrian traditions from Argentina to Canada.

Montauk, New York, on Long Island makes a somewhat debatable claim of having the oldest cattle operation in what today is the United States, having run cattle in the area since European settlers purchased land from the Indian people of the area in 1643. Although there were substantial numbers of cattle on Long Island, as well as the need to herd them to and from Common grazing lands on a seasonal basis, no consistent "cowboy" tradition developed amongst the cattle handlers of Long Island, who actually lived with their families in houses built on the pasture grounds. The only actual "cattle drives" held on Long Island consisted of one drive in 1776, when the Island's cattle were moved in a failed attempt to prevent them from being captured by the British during the American Revolution, and three or four drives in the late 1930s, when area cattle were herded down Montauk Highway to pasture ground near Deep Hollow Ranch.

The word "cowboy" appeared in the English language by 1725. It appears to be a direct English translation of vaquero, a Spanish word for an individual who managed cattle while mounted on horseback. It was derived from vaca, meaning "cow," which came from the Latin word vacca. Another English word for a Cowboy, buckaroo, is an anglicization of vaquero.

Captain George Vancouver brought cattle and sheep in 1793 as a gift to Kamehameha I, monarch of the Hawaiian Kingdom. For 10 years, Kamehameha forbade killing of cattle, and imposed the death penalty on anyone who violated his edict. As a result, numbers multiplied astonishingly, and were wreaking havoc throughout the countryside. By the reign of Kamehameha III the number of wild cattle were becoming a Problem, so in 1832 he sent an emissary to California, then still a part of Mexico. He was impressed with the skill of the vaqueros, and invited three to Hawai'i to teach the Hawaiian people how to work cattle.

In the 18th century, the residents of Spanish Texas began to herd cattle on horseback to sell in Louisiana, both legally and illegally. Their horses were of jennet type which became the Spanish Mustang. By the early 19th century, the Spanish Crown, and later, independent Mexico, offered empresario grants in what would later be Texas to non-citizens, such as settlers from the United States. In 1821, Stephen F. Austin led a group which became the first English-speaking Mexican citizens. Following Texas independence in 1836, even more Americans immigrated into the empresario ranching areas of Texas. Here the settlers were strongly influenced by the Mexican vaquero culture, borrowing vocabulary and attire from their counterparts, but also retaining some of the livestock-handling traditions and culture of the Eastern United States and Great Britain. The Texas Cowboy was typically a bachelor who hired on with different outfits from season to season.

The word buckaroo is generally believed to be an anglicized version of vaquero and shows phonological characteristics compatible with that origin. Buckaroo first appeared in American English in 1827. The word may also have developed with influences from the English word "buck" or bucking, the behavior of young, untrained horses. In 1960, one etymologist suggested that buckaroo derives, through Gullah: buckra, from the Ibibio and Efik: mbakara, meaning "white man, master, boss". Although that derivation was later rejected, another possibility advanced was that "buckaroo" was a pun on vaquero, blending both Spanish and African sources.

Geography, climate and cultural traditions caused differences to develop in cattle-handling methods and equipment from one part of the United States to another. The period between 1840 and 1870 marked a mingling of cultures when English and French-descended people began to settle west of the Mississippi River and encountered the Spanish-descended people who had settled in the parts of Mexico that later became Texas and California. In the modern world, remnants of two major and distinct Cowboy traditions remain, known today as the "Texas" tradition and the "Spanish", "Vaquero", or "California" tradition. Less well-known but equally distinct traditions also developed in Hawaii and Florida. Today, the various regional Cowboy traditions have merged to some extent, though a few regional differences in equipment and riding style still remain, and some individuals choose to deliberately preserve the more time-consuming but highly skilled techniques of the pure vaquero or "buckaroo" tradition. The popular "horse whisperer" style of natural horsemanship was originally developed by practitioners who were predominantly from California and the Northwestern states, clearly combining the attitudes and philosophy of the California vaquero with the equipment and outward look of the Texas Cowboy.

As English-speaking traders and settlers expanded westward, English and Spanish traditions, language and culture merged to some degree. Before the Mexican-American War in 1848, New England merchants who traveled by ship to California encountered both hacendados and vaqueros, trading manufactured goods for the hides and tallow produced from vast cattle ranches. American traders along what later became known as the Santa Fe Trail had similar contacts with vaquero life. Starting with these early encounters, the lifestyle and language of the vaquero began a transformation which merged with English cultural traditions and produced what became known in American culture as the "cowboy".

Likewise, Cowboys in movies were often shown fighting with American Indians. However most armed conflicts occurred between Native people and cavalry units of the U.S. Army. Relations between Cowboys and Native Americans were varied but generally not particularly friendly. Native people usually allowed cattle herds to pass through for a toll of ten cents a head, but raided cattle drives and ranches in times of active white-Native conflict or food shortages. In the 1860s, for Example, the Comanche created problems in Western Texas. Similar attacks also occurred with the Apache, Cheyenne and Ute Indians. Cowboys were armed against both predators and human thieves, and often used their guns to run off people of any race who attempted to steal, or rustle cattle.

Prior to the mid-19th century, most ranchers primarily raised cattle for their own needs and to sell surplus meat and hides locally. There was also a limited market for hides, horns, hooves, and tallow in assorted Manufacturing processes. While Texas contained vast herds of stray, free-ranging cattle available for free to anyone who could round them up, prior to 1865, there was little demand for beef. However, at the end of the American Civil War, Philip Danforth Armour opened a meat packing plant in Chicago, which became known as Armour and Company. With the expansion of the meat packing industry, the demand for beef increased significantly. By 1866, cattle could be sold to northern markets for as much as $40 per head, making it potentially profitable for cattle, particularly from Texas, to be herded long distances to market.

The first large-scale effort to drive cattle from Texas to the nearest railhead for shipment to Chicago occurred in 1866, when many Texas ranchers banded together to drive their cattle to the closest point that railroad tracks reached, which at that time was in Sedalia, Missouri. However, farmers in eastern Kansas, afraid that Longhorns would transmit cattle fever to local animals as well as trample crops, formed groups that threatened to beat or shoot cattlemen found on their lands. Therefore, the 1866 drive failed to reach the railroad, and the cattle herds were sold for low prices. However, in 1867, a cattle shipping facility was built west of farm country around the railhead at Abilene, Kansas, and became a center of cattle shipping, loading over 36,000 head of cattle that year. The route from Texas to Abilene became known as the Chisholm Trail, after Jesse Chisholm, who marked out the route. It ran through present-day Oklahoma, which then was Indian Territory. Later, other trails forked off to different railheads, including those at Dodge City and Wichita, Kansas. By 1877, the largest of the cattle-shipping boom towns, Dodge City, Kansas, shipped out 500,000 head of cattle.

There are few records mentioning girls or women working to drive cattle up the cattle trails of the Old West. However women did considerable ranch work, and in some cases (especially when the men went to war or on long cattle drives) ran them. There is little doubt that women, particularly the wives and daughters of men who owned small ranches and could not afford to hire large numbers of outside laborers, worked side by side with men and thus needed to ride horses and be able to perform related tasks. The largely undocumented contributions of women to the west were acknowledged in law; the western states led the United States in granting women the right to vote, beginning with Wyoming in 1869. Early Photographers such as Evelyn Cameron documented the life of working ranch women and cowgirls during the late 19th and early 20th century.

Barbed wire, an innovation of the 1880s, allowed cattle to be confined to designated areas to prevent overgrazing of the range. In Texas and surrounding areas, increased population required ranchers to fence off their individual lands. In the north, overgrazing stressed the open range, leading to insufficient winter forage for the cattle and starvation, particularly during the harsh winter of 1886–1887, when hundreds of thousands of cattle died across the North West, leading to collapse of the cattle industry. By the 1890s, barbed wire fencing was also standard in the northern plains, railroads had expanded to cover most of the nation, and meat packing plants were built closer to major ranching areas, making long cattle drives from Texas to the railheads in Kansas unnecessary. Hence, the age of the open range was gone and large cattle drives were over. Smaller cattle drives continued at least into the 1940s, as ranchers, prior to the development of the modern cattle truck, still needed to herd cattle to local railheads for transport to stockyards and packing plants. Meanwhile, ranches multiplied all over the developing West, keeping Cowboy employment high, if still low-paid, but also somewhat more settled.

It wasn't until the advent of Wild West Shows that "cowgirls" came into their own. These adult women were skilled performers, demonstrating riding, expert marksmanship, and trick roping that entertained audiences around the world. Women such as Annie Oakley became household names. By 1900, skirts split for riding astride became popular, and allowed women to compete with the men without scandalizing Victorian Era audiences by wearing men's clothing or, worse yet, bloomers. In the movies that followed from the early 20th century on, cowgirls expanded their roles in the popular culture and movie designers developed attractive clothing suitable for riding Western saddles.

"Cowboy" as an adjective for "reckless" developed in the 1920s. "Cowboy" is sometimes used today in a derogatory sense to describe someone who is reckless or ignores potential risks, irresponsible or who heedlessly handles a sensitive or dangerous task. TIME Magazine referred to President George W. Bush's foreign policy as "Cowboy diplomacy", and Bush has been described in the press, particularly in Europe, as a "cowboy".

Outside of the United States, the Cowboy has become an archetypal image of Americans abroad. In the late 1950s, a Congolese youth subculture calling themselves the Bills based their style and outlook on Hollywood's depiction of Cowboys in movies. Something similar occurred with the term "Apache", which in early 20th century Parisian society was a slang term for an outlaw.

In English-speaking regions outside North America, such as the British Isles and Australasia, "cowboy" can refer to a tradesmen whose work is of shoddy and questionable value, e.g., "a Cowboy plumber". The term also lent itself to the British 1980s TV sitcom, Cowboys. Similar usage is seen in the United States to describe someone in the skilled trades who operates without proper training or licenses. In the eastern United States, "cowboy" as a noun is sometimes used to describe a fast or careless driver on the highway.

Historian Terry Jordan proposed in 1982 that some Texan traditions that developed—particularly after the Civil War—may trace to colonial South Carolina, as most settlers to Texas were from the southeastern United States. However, these theories have been called into question by some reviewers. In a subsequent work, Jordan also noted that the influence of post-War Texas upon the whole of the frontier Western Cowboy tradition was likely much less than previously thought.

The United States Bureau of Labor Statistics collects no figures for Cowboys, so the exact number of working Cowboys is unknown. Cowboys are included in the 2003 category, Support activities for animal production, which totals 9,730 workers averaging $19,340 per annum. In addition to Cowboys working on ranches, in stockyards, and as staff or competitors at rodeos, the category includes farmhands working with other types of livestock (sheep, goats, hogs, chickens, etc.). Of those 9,730 workers, 3,290 are listed in the subcategory of Spectator Sports which includes rodeos, circuses, and theaters needing livestock handlers.

In 2005, the United States Senate declared the fourth Saturday of July as "National Day of the American Cowboy" via a Senate resolution and has subsequently renewed this resolution each year, with the United States House of Representatives periodically issuing statements of support. The long history of the West in popular culture tends to define those clothed in Western clothing as Cowboys or cowgirls whether they have ever been on a horse or not. This is especially true when applied to entertainers and those in the public arena who wear western wear as part of their persona. However, the reality is that many people, particularly in the West, including lawyers, Bankers, and other white collar professionals wear elements of Western clothing, particularly Cowboy boots or hats, as a matter of form even though they have other jobs. Conversely, some people raised on ranches do not necessarily define themselves Cowboys or cowgirls unless they feel their primary job is to work with livestock or if they compete in rodeos.

Because of the time and physical ability needed to develop necessary skills, the Cowboy often began his career as an adolescent, earning wages as soon as he had enough skill to be hired, (often as young as 12 or 13) and who, if not crippled by injury, might handle cattle or horses for the rest of his working life. In the United States, a few women also took on the tasks of ranching and learned the necessary skills, though the "cowgirl" (discussed below) did not become widely recognized or acknowledged until the close of the 19th century. On western ranches today, the working Cowboy is usually an adult. Responsibility for herding cattle or other livestock is no longer considered a job suitable for children or early adolescents. However, both boys and girls growing up in a ranch environment often learn to ride horses and perform basic ranch skills as soon as they are physically able, usually under adult supervision. Such youths, by their late teens, are often given responsibilities for "cowboy" work on the ranch.

Actual Cowboys have derisive expressions for individuals who adopt Cowboy mannerisms as a fashion pose without any actual understanding of the culture. For Example, a "drugstore cowboy" means someone who wears the clothing but does not actually sit upon anything but the stool of the drugstore soda fountain—or, in modern times, a bar stool. Similarly, the phrase "all hat and no cattle" is used to describe someone (usually male) who boasts about himself, far in excess of any actual accomplishments. The word "dude" (or the now-archaic term "greenhorn") indicates an individual unfamiliar with Cowboy culture, especially one who is trying to pretend otherwise.

Large numbers of cattle lived in a semi-feral, or semi-wild state on the open range and were left to graze, mostly untended, for much of the year. In many cases, different ranchers formed "associations" and grazed their cattle together on the same range. In order to determine the ownership of individual animals, they were marked with a distinctive brand, applied with a hot iron, usually while the cattle were still young calves. The primary cattle breed seen on the open range was the Longhorn, descended from the original Spanish Longhorns imported in the 16th century, though by the late 19th century, other breeds of cattle were also brought west, including the meatier Hereford, and often were crossbred with Longhorns.

In the 18th century, Creek, Seminole, and other Indian people moved into the depopulated areas of Florida and started herding the cattle left from the Spanish ranches. In the 19th century, most tribes in the area were dispossessed of their land and cattle and pushed south or west by white settlers and the United States government. By the middle of the 19th century white ranchers were running large herds of cattle on the extensive open range of central and southern Florida. The hides and meat from Florida cattle became such a critical supply item for the Confederacy during the American Civil War that a "Cow Cavalry" was organized to round up and protect the herds from Union raiders. After the Civil War, and into the 20th Century, Florida cattle were periodically driven to ports on the Gulf of Mexico, such as Punta Rassa near Fort Myers, Florida, and shipped to market in Cuba.

In Australia, where ranches are known as stations, Cowboys are known as stockmen and ringers, (jackaroos and jillaroos who also do stockwork are trainee overseers and property managers). The Australian droving tradition was influenced by Americans in the 19th century, and as well as practices imported directly from Spain. The adaptation of both of these traditions to local needs created a unique Australian tradition, which also was strongly influenced by Australian indigenous people, whose knowledge played a key role in the success of cattle ranching in Australia's climate.