[5] In September 2002, the yearling was consigned by the Pipers Hill Stud to the Tattersalls Houghton Sale at Newmarket and was bought for 150,000 guineas by the bloodstock agents McKeever St Lawrence.
He took the lead inside the final furlong, but was unable to pull away from his rivals, winning by a head from Meath, an Aidan O'Brien-trained colt to whom he was conceding five pounds.
The grey colt raced behind the leaders before moving up to third place behind North Light and Rule of Law with a quarter mile left to run.
He overtook North Light just inside the final furlong and stayed on to defeat the English Derby winner by half a length, with the 150/1 outsider Tycoon taking third place.
[12] After a break of 2+1⁄2 months, Grey Swallow returned for the Irish Champion Stakes over one a and a quarter miles at Leopardstown on 11 September in which he was matched for the first time against older horses.
Smullen, riding on his 28th birthday, settled the grey in fourth place before moving steadily forward in the straight to take the lead 1+1⁄2 furlongs from the finish.
[16] After a break of two months, Grey Swallow contested Britain's most prestigious all-aged race, the King George VI and Queen Elizabeth Stakes, which was run that year at Newbury Racecourse.
Starting the 100/30 second favourite, but after making a forward move with a half a mile to run, he faded in the closing stages and finished seventh of the twelve runners behind Azamour.
The horse's next race was the Irish Champion Stakes in September, in which he faced a field which included Azamour, Motivator, Oratorio and Alexander Goldrun.
[17] In the early summer of 2006, Grey Swallow was sent to North America for two races in which he was owned by Vega FZE and ridden by Alex Solis.
On 13 May, carrying top weight of 121 pounds, he started 3/5 favourite for the Grade II Jim Murray Memorial Handicap at Hollywood Park Racetrack.
[23] Grey Swallow was retired from racing to stand as a breeding stallion in Australia, based at the Woodside Park Stud in Victoria.