A bay gelding by Archive out of Bright Cherry, Arkle was the grandson of the unbeaten (in 14 races) flat racehorse and prepotent sire Nearco.

Trained by Tom Dreaper at Greenogue, Kilsallaghan, in County Dublin, he was ridden during his steeplechasing career by Pat Taaffe.

Arkle won three Cheltenham Gold Cups and a number of other top races before his career was cut short by injury.

Arkle, a bay colt with no white markings, was bred by Mary Baker, who kept a few mares on the family farm at Malahow, near Naul in County Dublin.

[1]: 10–11, 14 In August 1960, the yet unnamed gelding was sent to Goff's Bloodstock Sales in Ballsbridge, Dublin, where he was bought for 1,150 guineas by Tom Dreaper on behalf of the Duchess of Westminster.

After spending a year at Eaton Hall, the Westminster estate in Cheshire, Arkle returned to Ireland in August 1961 to go into training at Tom Dreaper's yard, Greenogue, at Kilsallaghan, north of Dublin.

The pair then finished fourth in the New Handicap Hurdle at Fairyhouse, before Arkle went to spend the summer on his owner's farm at Bryanstown House, Maynooth, County Kildare.

[1]: 38 Arkle started the season with a win in the Donoughmore Plate, a flat race at Navan, in which he was ridden by former champion jockey T. P. Burns.

Arkle was just a length behind the leader Mill House at the third last, when he slipped after landing and took a while to recover his momentum, finishing in third place.

The racing authorities in Ireland took the unprecedented step in the Irish Grand National of devising two weight systems – one to be used when Arkle was running, and one when he was not.

[1]: 70 After a warm-up race in Ireland, Arkle returned to Newbury to avenge his defeat by Mill House in the previous year's Hennessy Gold Cup.

In spite of giving away at least 35 lbs to his six rivals, Arkle won by five lengths and netted the largest prize of his career to date, £8,230.

Without a preparatory race, having not run for eight months and having suffered a setback in training two weeks earlier, faced five rivals all of whom carried at least 33lbs less than him.

[1]: 132-136 Arkle returned to his winning ways eighteen days later, when he landed the SGB Handicap Chase at Ascot carrying his usual top weight of 12st 7lbs.

On 27 December 1966, Arkle ran in the King George VI Chase at Kempton Park but struck the guard rail with a hoof when jumping the open ditch, which resulted in a fractured pedal bone; despite this injury, he completed the race and was only overtaken on the run-in to finish second, a half-length behind the winner, Dormant, to whom he was still conceding 21lbs.

[1]: 144-148  Visibly lame, Arkle was loaded into the horse-ambulance and taken back to the racecourse stables, where he remained for two months, his injured leg encased in plaster.

He was retired and ridden as a hack at Bryanstown by his owner but in 1969 his condition deteriorated and he began to show signs of stiffness in his hind legs, possibly due to arthritis.

[3] In 2004 he narrowly beat Desert Orchid to be named all-time favourite British or Irish racehorse in a Racing Post poll.

In 1976, the controversial decision was made to exhume Arkle's remains and to mount his skeleton for display at the Irish National Stud.