Amateur career

McIlroy was a member of Europe's winning 2004 Junior Ryder Cup team. In 2005 he became the youngest ever winner of both the West of Ireland Championship and the Irish Close Championship. He retained the West of Ireland Championship in 2006 and followed that up with back to back wins at the Irish Close Championship. In August 2006 he won the European Amateur Championship at Biella Golf Club, near Milan, Italy.

In July 2005 he shot a course record 61 at Royal Portrush Golf Club. In October 2006 McIlroy represented Ireland in the Eisenhower Trophy, the Amateur World Team Championship. On 6 February 2007 he became the second man to top the World Amateur Golf Rankings, though he lost the top spot after just one week.

McIlroy shot an opening round of 3 under par 68 at the 2007 Open Championship at Carnoustie which put him in a tie for third place, three shots off the lead. He was also the only person in the field without a bogey in the first round. He then shot a 5 over par 76 in round two to leave him on +2 for the championship, comfortably making the cut. In the third round he shot a 2 over par 73. In the final round he shot a 72 (+1) to finish at T42. He shot +5 overall.

McIlroy was part of the Great Britain & Ireland team at the 2007 Walker Cup. On the first day of the event McIlroy was paired with Jonathan Caldwell for morning foursomes and the match was halved. In the afternoon he faced Billy Horschel in singles but Horschel won 1 up. On the second day McIlroy and Caldwell lost in morning foursomes by the score of 2 & 1. In the afternoon he faced Billy Horschel in singles again and this time he won by the score of 1 up. McIlroy's overall record was (1-2-1) in Win-Loss-Tie format. In the end the United States came out victorious by a score of 12½ to 11½.

McIlroy made his first appearance in a European Tour event a few days after turning sixteen, when he took part in the 2005 British Masters. He made the cut on the European Tour for the first time as a seventeen year old at the 2007 Dubai Desert Classic, where he had to forego prize money of over €7,600 due to his amateur status.

Amateur wins

• 2005 (2) West of Ireland Championship, Irish Close Championship
• 2006 (3) West of Ireland Championship, Irish Close Championship, European Amateur Championship

Professional career 2007

McIlroy turned professional on September 19 which was the day before the Quinn Direct British Masters. He signed with International Sports Management, a company that also manages Ernie Els, Darren Clarke, Lee Westwood and David Howell. At the British Masters, McIlroy shot 290 (+2) which put him in a tie for 42nd place. McIlroy finished in 3rd place at the Alfred Dunhill Links Championship in October. He finished 3 strokes behind the winner Nick Dougherty. Due to this performance, McIlroy put himself in position to become the youngest Affiliate Member in the history of The European Tour to earn a tour card. The next week McIlroy secured his card for 2008 by finishing in a tie for 4th place at the Madrid Open. On the 2007 European Tour season, McIlroy earned €277,255 and finished in 95th place on the Order of Merit list. He was the highest ranked associate member.

2008

Before his season started, Tiger Woods invited McIlroy to play in the 2007 Target World Challenge. He declined the invitation though, saying, "I was thrilled that they would want to invite me considering I'm only just starting out on my career." McIlroy also said "That event clashes with the European Open and that's an event I would be stupid not to play."

McIlroy started his 2008 European Tour season at the UBS Hong Kong Open. He did not make the one-under cut though, missing it by four strokes. He shot a 69 in the 1st round and looked good to make the cut from there. McIlroy slipped up in the 2nd round though and shot a 74. This poor round made him miss his first cut as a professional. McIlroy bounced back by finishing in a tie for 15th at the MasterCard Masters in Australia.

McIlroy entered the top 200 of the Official World Golf Rankings for the first time on January 27 2008.