Since 2017, Rory McIlroy's best friend, Harry Diamond has been his full-time caddie out on tour. The pair grew up together in Holywood, County Down and have been friends since their junior days at Holywood Golf Club.
Diamond was a good player in his own right - representing Ireland as a youngster - but did not make it as a pro and was hired as McIlroy's on-course companion in 2017 when the former World No.1 split with JP Fitzgerald after eight years and four Majors together.
Since then, the childhood friends have become one of the most successful partnerships anywhere in the game thanks to a first Masters title in 2025 and several more PGA Tour or DP World Tour victories beside.
Not only that, but McIlroy and Diamond have clinched three Race To Dubai prizes and two FedEx Cups, with the season-long competitions featuring some mind-blowing checks, too - each of which could have been partially shared with Diamond as a thank you for his hard work.
Then there are the initiatives like the Player Impact Program which might have seen a small portion handed over on top of Diamond's weekly or annual base salary.
Although McIlroy will take home the overwhelming majority of said money, understandably so, there is a common theory that loopers have between five and 10% of the weekly prize money (providing their boss makes the cut) shared with them as a bonus, depending on where on the leaderboard the player finishes. The 10% figure may possibly extend to one-off bonuses like the PIP, too.
If a golfer wins a tournament, a caddie might well expect to receive 10% of the prize money. Should the player finish elsewhere in the top-10 then it might drop to 7% or so, and anything outside of the top-20 is almost certain to see the bagman pick up a much smaller pay packet - perhaps as little as an extra 5%.
But given McIlroy's regular ability to finish at the top of the pile, Diamond could be banking plenty of extra money at an impressive rate.
If we consider how much Diamond might have earned in 2025, two victories at prestigious PGA Tour events through the first quarter of the year could easily have helped the caddie collect almost $900,000 in bonuses - an outstanding figure when you consider that was over $100,000 higher than the average figure a PGA Tour player had banked at the time.
That sort of number could be becoming the norm for the Northern Irishman, though, with McIlroy regularly scoring well over $10 million in prize money in recent seasons. Even at a rough average of 7%, Diamond's bonus check is likely to have been seven figures since 2021-22.
If you're the caddie of McIlroy, the good news doesn't stop there because bonus money does not take into account the annual baseline salary that McIlroy will be paying him, either.
For the average caddie on tour, experienced PGA Tour looper, Brennan Little told Golf Monthly that around $2,000 per week is the usual fee, but "everything is worked out between you and the player."
Little continued: "After a few years you’ll get a raise. Or you’ll get bonuses at the end of the year. It just varies by the player. I think generally if you were looking for a number it would be $2,000 a week, and then 7 to 8 per cent and 10 per cent.”
However, for a player like McIlroy - who is reportedly worth around $225 million and sits high up on the career money list for whichever tours he competes on - Diamond is likely to be compensated much more handsomely.
Given the exact numbers of anyone's salary is private information, gauging an accurate estimation of how much Diamond actually earns is impossible. However, based on the factors we understand to be true, listed above, it is possible to provide a sensible educated guess.
