The breed is very old, possibly from before AD 1, created by the Celts as Cú Faoil. Due to a massive export into various countries as a gift for royalty and a ban that allowed only royalty to own such a dog, the breed almost vanished in the middle of the 19th century. Captain Graham rebred the Irish Wolfhound with the Deerhound, Great Dane, and other breeds; this saved the breed, but had the inevitable effect of altering its appearance. Their average lifespan is around 6 to 7 years.
Supplemental calcium shots, minerals, and vitamins need to be administered until a certain age. By the age of 8 months, the dogs appear adult, and many owners start stressing them too much. Outstretched limbs and irreparable damage are the result. Wolfhounds need at least 18 months to be ready for lure coursing, running as a sport, and other strenuous activities.
In temperament, they are considered gentle and friendly, very calm in the house, enjoying long sleeps but energetic when taken for walks. Despite their great size and sometimes intimidating appearance, wolfhounds are sensitive and should be corrected firmly but without anger. They should be socialized from a young age so that they have a chance to gather experience.
The Irish Wolfhound is usually known as the tallest dog in the world, averaging up to 86 cm (34 inches) at the withers, a fact that sometimes is its biggest disadvantage when attracting owners who have no concern for its special needs. As with all breeds, the ideal and accepted measurements vary somewhat from one standard to another, and there will always be individuals whose size falls outside these standards. However, generally breeders aim for a height averaging 32 to 34 inches (81 cm to 86 cm) in male dogs, two to four inches (5 to 10 cm) less for bitches. Acceptable weight minimums range from 105 lb (48 kg) for bitches to 120 lb (54 kg) for males.
An Irish Wolfhound serves as the regimental mascot to the Irish Guards in England and accompanies the regiment in all of its parades.