Draft horses are recognizable by their extremely muscular build. They tend to have broad, short backs with powerful hindquarters. In general, they are taller and tend to have heavier bone and a more upright shoulder than riding horses, producing conformation that is well suited for pulling. Many draft breeds have heavier hair, called feathering on their lower legs. Draft breeds range from approximately 163 to 193 cm (16 to 19 hands) high and from 640 to 910 kg (1,400 to 2,000 lb).

Humans domesticated horses and used them to perform a variety of duties. One type of horse-powered work was the hauling of heavy loads, plowing fields, and other tasks that required pulling ability. A heavy, calm, patient, and well-muscled animal was desired for this work. Conversely, a light, more energetic horse was needed for riding and rapid transport. Thus, to the extent possible, a certain amount of selective breeding was used to develop different types of horse for different types of work.

It is a common misunderstanding that the Destrier that carried the armoured knight of the Middle Ages had the size and conformation of a modern draft horse, and some of these Medieval war horses may have provided some bloodlines for some of the modern draft breeds. The reality was that the high-spirited, quick-moving Destrier was closer to the size, build, and temperament of a modern Andalusian or Friesian. There also were horses of more phlegmatic temperaments used for pulling military wagons or performing ordinary farm work which provided bloodlines of the modern draft horse. Records indicate that even medieval drafts were not as large as those today. Of the modern draft breeds, the Percheron probably has the closest ties to the medieval war horse.^[1]

By the 19th century horses weighing more than 730 kilograms (1,600 lb) that also moved at a quick pace were in demand. Tall stature, muscular backs, and powerful hindquarters made the draft horse a source of horsepower for farming, hauling freight and moving passengers. The advent of railroads increased demand for working horses, as a growing economy still needed transport over the 'last mile' between the goods yard or station and the final customer.^[2] Even in the 20th century, until motor vehicles became an affordable and reliable substitute, draft horses were used for practical work.

Over half a million draft horses were used during World War I. The British were importing American draft horses to supplement their dwindling stock even before America joined the war, preferring Percheron crosses which they said had "great endurance, fine physique, soundness, activity, willingness to work, and almost unfailing good temper". British buyers were buying 10,000 to 25,000 American horses and mules a month, eventually making up about two-thirds of British Army war horses.^[3]: 118

In the late 19th century and early 20th century, thousands of draft horses were imported from Western Europe into the United States. Percherons came from France, Belgians from Brabant, Shires from England, Clydesdales from Scotland. Many American draft breed registries were founded in the late 19th century. The Percheron, with 40,000 broodmares registered as of 1915, was America's most numerous draft breed at the turn of the 20th century.^[1] A breed developed exclusively in the U.S. was the American Cream Draft, which had a stud book established by the 1930s.

Beginning in the late 19th century, and with increasing mechanization in the 20th century, especially following World War I in the US and after World War II in Europe, the popularity of the internal combustion engine, and particularly the tractor, reduced the need for the draft horse. Many were sold to slaughter and a number of breeds went into significant decline.^{[4]: 141, 348, 362}

Today, draft horses can be seen in horse shows, pulling competitions, heavy horse trials, parades pulling large wagons, pulling tourist carriages, and they are still seen on some smaller farms in the US and Europe. They are still used by agrarian groups such as the Amish and Mennonites. Draft horses are used for logging in dense woodland where there is insufficient space for mechanized vehicles or for other conservation considerations.

Draft horse breeds have played a significant role in the development of many warmblood breeds, popular today in advanced level equine sports.

Small areas still exist where draft horses are widely used as transportation due to legislation preventing automotive traffic, such as on Mackinac Island in the United States.

Management of a large draft horse can be costly, including feed, shoeing, and veterinary care. Although many draft horses can work without a need for shoes, if they are required, farriers may charge twice the price to shoe a draft horse as a light riding horse because of the extra labor and specialized equipment required.^[5] Historically, draft horses were shod with horseshoes that were significantly wider and heavier than those for other types of horses, custom-made, often with caulkins.^[6]

The draft horse's metabolism is a bit slower than lighter horse breeds, more akin to that of ponies, requiring less feed per pound of body weight. This is possibly due to their calmer nature. Nonetheless, because of their sheer size, most require a significant amount of feed per day. Generally a supplement to balance nutrients is preferred over a large quantity of grain. They consume hay or other forage from 1.5% to 3% of their body weight per day, depending on work level. They also can drink up to 95 litres; 21 imperial gallons (25 US gal) of water a day. Overfeeding can lead to obesity, and risk of laminitis can be a concern.^[7]

The largest horse in recorded history was probably a Shire born in 1846 named Sampson (renamed Mammoth). He stood 218 cm (21.2 hands) high, and his peak weight was estimated at 1,524 kilograms (3,360 lb).^[8][9]

At over 193 cm (19 hands), a Shire gelding named Goliath (1977–2001) was the Guinness Book of World Records record holder for the world's tallest living horse (until his death).^[10][11] Big Jake (2001–2021), an American Belgian standing 210.2 cm (20.275 hands), held the record for tallest living horse from 2010 until his death in 2021. As of 2024, there is no living record holder.^[9]

The following breeds of horse are considered draft breeds:^{[12][13][14][15]}

• Driving (horse)
• Heavy warmblood
• Working animal § Draft animals
• Ox § Uses and comparison to horses
• Meat horse – Horses bred specifically for horse meat