2012: two-year-old season Magician began his racing career in a seven
furlong maiden race at
Leopardstown Racecourse on 8 September. Ridden by
Seamie Heffernan he started at odds of
10/1 and finished ninth of the sixteen runners behind Mooqtar. Nineteen days later he ran in a similar event at
Dundalk and was ridden by his trainer's son
Joseph O'Brien to finish second, half a
length behind the
Dermot Weld-trained favourite Mouteab. Joseph O'Brien rode the colt again when he started 4/5 favourite for a maiden race at the
Curragh on 14 October. Racing over a mile on heavy ground, Magician took the lead inside the final quarter mile and drew clear of his opponents in the closing stages to win by six lengths from Bunairgead. Two weeks later, Magician was moved up in class to contest the
Group Three Killavullan Stakes over seven furlongs at Leopardstown. Seamie Heffernan sent the colt into an early lead, but after being overtaken, and then badly hampered in the straight, Magician was eased down to finish last of the seven runners behind Big Break.
2013: three-year-old season On his first appearance of 2013, Magician was sent to the United Kingdom on 10 May to contest the
Dee Stakes at
Chester Racecourse, a race regarded as a trial for
The Derby. Ridden by
Ryan Moore, he started the 13/8 favourite for the nine furlong race against four British-trained opponents. Magician tracked the leader Gabrial's Kaka before moving to the outside in the straight, taking the lead, and pulling clear to win by four lengths from Contributor. After the race Moore described him as "a very nice horse... he really quickened very well." Magician's win saw him enter the ante-post betting for the Derby, with bookmakers offering him at odds of 14/1. Fifteen days after his win at Chester, Magician started the 100/30 second favourite for the Irish 2000 Guineas at the Curragh, with the
Richard Hannon Sr.-trained Van der Neer heading the betting after finishing third to
Dawn Approach in the English
2000 Guineas at
Newmarket. Ridden by Joseph O'Brien, Magician was settled just behind the leaders before moving to the front approaching the final furlong. In the closing stages he accelerated clear of the field and won "comfortably" by three and a half lengths from his stable companion Gale Force Ten. Magician's Derby odds were cut to 6/1 after the race, but Coolmore's owner John Magnier declined to commit the horse to the race, saying that he had "all kinds of options." Magician did not contest the Derby (won by his stable companion
Ruler of the World), but was instead aimed at the
St James's Palace Stakes at
Royal Ascot. He started the 5/2 second favourite behind the
2000 Guineas winner
Dawn Approach but was badly hampered early in the straight and finished last of the nine runners after being eased down in the closing stages. Magician was off the course for four and a half months before his next start, the
Breeders' Cup Turf at
Santa Anita Park on 2 November. The colt was matched against older horses for the first time and tested over one and a half miles, three furlongs further than he had run before. Ridden by Ryan Moore, he was held up at the back of the field before producing a strong run in the straight to win by half a length from
The Fugue. In November, Magician was voted Champion Three-year-old Colt at the
Cartier Racing Awards.
2014: four-year-old season On his four-year-old debut, Magician started the 5/2 favourite for the
Dubai Sheema Classic at
Meydan Racecourse on 29 March 2014. Ridden by Joseph O'Brien, he never looked likely to win but stayed on in the closing stages to finish sixth of the fifteen runner behind the Japanese mare
Gentildonna. He recorded his first win of the season in the
Mooresbridge Stakes at the Curragh on 5 May beating Parish Hall by a neck at odds of 2/13. Magician returned to Group One class on 25 May, when he started joint favourite for the Tatteralls Gold Cup at the Curragh. He made some progress in the straight but was never able to reach the lead and finished second, a length and a quarter behind
Noble Mission. At
Royal Ascot in June Magician started at odds of 6/1 for the
Prince of Wales's Stakes, a race which attracted a very strong field including
Treve,
The Fugue,
Mukhadram and
Dank. The colt was among the leaders from the start and took the lead in the straight, but was overtaken approaching the final furlong by The Fugue. He held on to take second place, one and three quarter lengths behind the winner and a length ahead of Treve. Magician started at odds of 9/2 for Britain's most prestigious
weight-for-age race the
King George VI and Queen Elizabeth Stakes at Ascot on 26 July but ran poorly and finished sixth of the eight runners, beaten fourteen lengths by the winner
Taghrooda. In August the colt was sent to the United States to contest the thirty-second running of the
Arlington Million and was made favourite at odds of 9/5. With no obvious front-runners in the race, Joseph O'Brien opted to employ new tactics as he disputed the lead from the start. He gained a narrow advantage in the straight but was caught 75 yards from the wire and beaten by the 11.5/1 outsider
Hardest Core. Magician returned to America to defend the Breeders' Cup Turf, but was withdrawn three days before the race after returning from exercise lame in his right foreleg. ==Assessment==