Early records of the antecedents of harness racing are ancient. Assyrian kings of 1500 BC maintained elaborate stables, and professional trainers for horses used to draw chariots (chariot racing), originally used in war but soon also used in the sport of hunting. Homer's account of the chariot race in the Iliad is later. There were four-horse hitch chariot races in the Olympic Games of the 7th century BC and races with two-horse hitches earlier. Horses were locally bred with others from Asia Minor and northern Africa.

Chariot racing came into great prominence as a sport after its transfer to Rome. Public records were kept of the bloodlines of horses; exceptional horses were buried with stelae giving their records (one had 1,300 first place victories, 88 second places, and 37 third places). A perfect site for chariot racing was found between the Palatine and Aventine hills, where the Circus Maximus was built. By the 4th century AD this hippodrome's permanent stands could hold 200,000 spectators. In Greece chariot racing had been a sport of rich men, but in Rome the sport involved companies, distinguished by their colours: white, red, blue, and green. In the reign of Augustus (27 BC–AD 14), there were 12 races a day; by Flavius' reign (69–96), the number rose to 100, from daybreak until sundown, the length of races being shortened to accommodate the larger number. The sport had professional racing officials, starting chutes, disputes at law, accusations of doping horses, widespread gambling (spectators wore their favourite company's colour), and riots. The chariot disappeared as a military vehicle and chariot racing ended with the fall of Rome in the 4th century; modern harness racing did not begin to evolve until early in the 19th century.

As early as 1554 the fastest of 3,000 horses at a horse fair in Valkenburg in Holland competed in trotting matches. The Golden Whip, Holland's most famous trotting event, was first run in 1777 at Soestdijk. About the same time Aleksey, Count Orlov (Orlov, Grigory Grigoryevich, Graf), began to develop a powerful trotting strain at his stud farm in Russia. From his stallion Barss came the Orlov trotter that became the foundation of Russian trotting stock.

England's Norfolk Trotter, which emerged as a breed around 1750, was purely a road horse, but its speed led to its being used for road racing as a diversion for its owners. Most of its matches were trotting a given distance within a specified time.

Trotting in North America also had its heritage in road racing, but in the early 19th century there were trotting tracks in the United States. Yankee trotted a mile over the track at Harlem, New York, in 1806 in 2:59. This time was lowered to 2:48 ¹/₂ by an unnamed trotting gelding from Boston at the Hunting Park track in Philadelphia in 1810. By midcentury harness racing also thrived at county fairs in the United States and agricultural fairs in eastern and central Canada.

By 1840 trotting was an organized sport in New England, and a new era was underway. In 1871 the Grand Circuit, originally known as the Quadrilateral Trotting Combination, was established and grew from 4 to 23 tracks. In 1879 the Standardbred horse was established in the United States, based on a standard of time performance—2 minutes 30 seconds—for one mile.

The creation and evolution of the Standardbred horse and that breed's impact on world trotting rested on the prepotency of the English Thoroughbred stallion Messenger, imported to Philadelphia in 1788. He became both a major contributor to the American Thoroughbred through his undefeated grandson American Eclipse, but also immortal for harness racing as a sire of Thoroughbred runners that became trotting stallions. Ten of his sons became leading trotting sires in the early 19th century, and his great-grandson Hambletonian 10, foaled in 1849, sired 1,331 sons and daughters between 1851 and 1875 and obliterated all other strains of the trotting horse in the United States. He founded a line so dominant that all American Standardbreds after him and many trotters in the rest of the world can be traced to him.

The American pacer (pacing) descended a different path from that of the trotter. Pacer heritage fuses the blood of the Narragansett pacer, a saddle horse that disappeared by 1850, and the Canuck of French Canada. The trotter began in the East, but the great growth of the pacer was in the Midwest and South, primarily in Ohio, Indiana, Kentucky, and Tennessee. Before the pacer attained popularity late in the 19th century, it was a despised horse.

Trotting spread rapidly, being introduced to France in 1836. In Italy there had been cart racing as early as 1808, but the introduction of French blood stock made it much more popular, as it did in Belgium and Holland. Sweden began harness racing in the 1880s, and Austria and Germany began late in the century. Only in Great Britain did it not take hold. U.S. stock was introduced to Australia and New Zealand, but real popularity there came only in the 20th century.

As American trotting moved from county and agricultural fairs to regular harness racing tracks, such champions as Lady Suffolk, nicknamed the “old gray mare”; Flora Temple, the “bobtailed mare” of the well-known song “Camptown Races”; the legendary Goldsmith Maid and Dexter; and especially the popular Maud S. led to extremely active European and worldwide interest in American breeding stock.

A rival of Lady Suffolk, the gelding Americus, had made a highly successful invasion against English road trotters in the 1850s, and in the same decade the trotting mares Lady Pierce and Miss Bell had been exported to France, where both raced well. Lady Pierce produced a line that led to Fuchsia, the greatest early trotting progenitor of the French breed. As the 19th century ended, American blood stock was introduced into virtually all trotting nations of the world. In the 1890s 2,000 American Standardbreds had been exported by 1898 and 3,000 by 1903. The American influence was to remain a dominant factor. Only in France and Russia was there resistance. The Orlovs remained dominant in Russia. The French had established their own breeds in the strong demisangs (half-bloods) of Normandy. The French closed their studbook to foreign horses in 1937.

The arrival of the Big Four—Mattie Hunter, Sleepy Tom, Rowdy Boy, and Lucy—in the 1870s; the coming of the first two-minute harness horse, the pacer Star Pointer in 1897; and the overwhelming popularity of Dan Patch in the early years of the 20th century did much to foster the popularity of pacers.

The modern harness racing vehicle developed from a single-seat pleasure conveyance. Earlier racing had used carts. In its final form it is little more than a U-shaped shaft mounted on two wheels with a seat at the end of the U. When it was introduced in harness racing early in the 19th century it weighed about 125 lb (56 kg), but by the 1870s it had been reduced to 46 lb (21 kg). The addition of ball bearings and pneumatic tires in the 1880s and of bicycle wheels in the 1890s established the present form, though there have been refinements. The driver's seat was lowered. When in 1903 the trotter Lou Dillon broke the two-minute mile barrier, his record was exceeded by only four horses through 1969. In the preceding 58 years the record had been successively lowered by half a minute. Lou Dillon's sulky weighed 25 lb (11.3 kg).

From the zenith at the turn of the 20th century, with popular horses, new records, and larger attendance, harness racing then declined, though it persisted at county fairs, on the Grand Circuit, and in Europe. Some attributed the change to the rise of the automobile and the passing of the road horse, though most racing had long been on tracks. Others attribute the decline to a revulsion from corruption arising from gambling, which resulted in fixed races, the disqualification of a racer for breaking gait or the pulling up of a horse by a driver being easily accomplished without provable detection.

Two changes turned the tide. pari-mutuel (q.v.) racing under lights was introduced at Roosevelt Raceway in New York City in 1940 (there had been occasional night racing in the 1890s and under the lights in Toledo, Ohio, in 1927); and the mobile starting gate (a pair of retractable metal wings mounted on the rear of an automobile that moves off slowly, getting the horses off to an even running start, and then accelerates away and off the track) was instituted, also at Roosevelt, in 1946.

The sport surged in some ways in the same manner as did horse racing on the flats. In the quarter century after 1948 attendance nearly tripled; state revenue increased nearly eightfold; purses nearly tenfold; the number of horses starting fourfold; and membership in the United States Trotting Association (founded in 1938 as a merger of other groups after the governance of harness racing had fallen into disarray) nearly quintupled.

The U.S. classic races show some difference. Of the trotting triple crown races, the Hambletonian (from 1926), Yonkers Futurity (from 1958), and the Kentucky Futurity (from 1893), one began in the revival period; and of the pacing triple crown races, the William H. Cane Futurity (from 1955), Messenger Stake (from 1957), and Little Brown Jug (from 1946), none dated before the revival period. These classic races preserved heat racing, a winner needing two heat victories; but generally races were at a mile.

Notable American horses included the trotter Greyhound in the 1930s, the pacers Adios in the 1940s and his son Adios Butler in the 1950s, the pacer Bret Hanover and the trotter Nevele Pride in the 1960s, and the pacer Niatross retired to stud in 1981. The French trotting mare Une de Mai was at one time one of the leading money winning horses in purses.

Harness racing expanded greatly in New Zealand and Australia, France, Italy, Sweden, Austria, and Russia. New York City's Roosevelt and Yonkers raceways, and Meadowlands in New Jersey dominate U.S. and Canadian harness racing; but there are major centres in Chicago, Philadelphia, and Los Angeles, and in Toronto and Montreal. Meanwhile, the county and state fair meets prosper. The advent of the Roosevelt International Trot in 1959, the International Pace series at Yonkers in the 1960s, and the introduction of the World Driving Championship in 1970 all fostered international competition.

By 1980 harness racing seemed to have no limit to its growth in purse amounts, attendance, stud fees, and prices paid for horses. The $1,000,000 earning horses were topped by $2,000,000 winners. A pace at Meadowlands in 1980 had a purse value of more than $2,000,000 with more than $1,000,000 going to the winner. Drugs used on horses for medication complicated the problem of controlling corruption. There was over-racing (a day's card was normally ten races). Harness racing and flat racing serve different constituencies, but a determined horseplayer could leave after the ninth race at a flat-course track and have time for a meal before the evening's harness racing began.