A string of consistent performances have seen him gradually rise in the ranking. It all began in the Fedex Cup last year when he was narrowly pipped to the $10million prize by Jim Furyk, before producing the best golf at a remarkable and unforgettable Ryder Cup.
The 33-year-old continued his impressive form at the start of this year, winning the WCG matchplay, before finishing tied fourth in the Masters, and then coming runner-up to Ian Poulter in the second World Matchplay event.
His consistency is summed up with this one stat - Donald has finished in the top 10 in 14 of the last 15 events. A staggering and brilliant statistic.
It's difficult to pinpoint exactly where and how Donald has improved so dramatically in such a short space of time.
Luke Donald has undoubtedly been the best player on the planet in 2011. His silky smooth swing never causes him to be off balance and rarely does he hit a wayward shot.
He has the all round game to someday win a major, there can be little doubt of that. Probably the current best putter in the game, Donald has displayed some incredible golf in recent months. Having won the matchplay without being behind is a remarkable achievement.
Many attributes make up a top class golfer but perhaps the most important is putting. It's the one area where Donald has improved. He rarely misses, in fact it's more rare for Fernando Torres to score a goal than for Luke Donald to miss within ten feet.
The calmness and composure of the man is another noticeable and major factor in his rise up the rankings. Rarely does Donald show any emotion. He quietly gets on with the job while others fret and panic around him. Even when he was making serene progress up the leaderboard on the last day of the Masters, there was little emotion. Only when he chipped in for birdie on the last did he react with a fist pump or two.
In the past, that absence of emotion has been mistaken for a lack of passion or willingness to win and succeed. But it's the type of guy he is. Comes across as laid back whereas in fact he's a passionate, hard-working golfer, who's desperate to succeed at the highest level.
The achievement of getting to world number one is even more remarkable given the modern game. It's becoming more about the big hitters, something which Donald is certainly not. He plots his way around the course, playing to his strengths and working out the best way to go about things.
Donald proves that you don't have to be a long hitter to succeed. As proved by the fact that he has played par 5s third best out of everyone on the PGA Tour this season.
Now he is number one, it's time for the ultimate goal - a major. He has the game and mentality to do it. To win a major you have to remain calm and composed and not get ruffled when the going gets tough. You also need that grit and determination to see yourself through that inevitable bad round.
Donald has these attributes in abundance, and he proved that during his PGA Championship win. He was far from his best but time and time again, he got himself out of trouble, displaying the steely grit and will to win needed to claim the top prizes.
And he didn't bottle it when it mattered. Playing the play-off hole against the number one golfer at the time, Lee Westwood, he produced four immaculate shots to birdie the hole and win the competition.
Now he has to bring all parts of his game together in a major championship, only then will he be remembered as a true great.
Donald has achieved an awful lot and, at 33, still has time to really impose himself into the golfing history books. There's no doubt he has the temperament and the game to win a major, but, as proved with Lee Westwood, it is never easy winning that first one.