Who Is Rory McIlroy's Caddie? Meet Harry Diamond

Rory McIlroy has already enjoyed a Hall of Fame career with four Major titles and close to 50 professional victories worldwide. Along the way, he has primarily been assisted by just a couple of caddies.

The first long-term looper was JP Fitzgerald. Their on-course partnership began in 2009 and lasted eight years, which were some of the former World No.1's best. The duo collected all four of McIlroy's biggest victories, a FedEx Cup and three Race To Dubai triumphs.

But following his first winless season since 2008, McIlroy and Fitzgerald parted ways in 2017 and a new bagman arrived on the scene. It was thought to be a short-term alliance at first, but McIlroy's current caddie, Harry Diamond has largely been with him ever since.

Another of his friends, Niall O'Connor, temporarily carried the bag in 2022 - during which time they won the RBC Canadian Open together - but Diamond quickly returned.

O’Connor, a friend who met McIlroy in his late teens, caddied for the Northern Irishman at the 2019 DP World Championship in Dubai. He played high-level rugby for Ulster and is also a keen golfer. That partnership came about because Diamond was expecting a second child with his wife.

McIlroy and Diamond are best friends after growing up together in Holywood, Northern Ireland and have a fantastic relationship and understanding on the golf course as well as off it.

Briefly explaining the pair's dynamic, McIlroy said: "I was an only child and Harry was a big brother. We’re very close. I love having him on the bag. I’m a different person. And I’m never going to give him sh** even if something goes wrong. It would not be worth it.” 

The pair, who have enjoyed 14 PGA Tour victories (and counting) together as well as two FedEx Cup triumphs in 2019 in 2022, have been friends since their junior days at Holywood Golf Club.

Diamond was also an outstanding player, representing Ireland as a youngster. In 2012, he won the West of Ireland Championship which earned him a spot at the Irish Open that year.

As well as being on McIlroy's bag, Diamond was also by his side as Best Man when his boss married Erica Stoll in County Meath in 2017. Diamond enjoyed a spell off studying yardage booklets to arrange the stag party in Miami. 

Away from the course, Diamond is fairly private, staying away from social media and saying very little about his work with McIlroy. He is believed to own a number of his own businesses, including several bars.

The pair are yet to win a Major together, something that is repeatedly pointed out with McIlroy having been stuck on four since 2014. But one of their high points came when Diamond talked McIlroy into taking a penalty drop at the 72nd hole of the 2021 Wells Fargo Championship. McIlroy readjusted to find the green and ultimately win at Quail Hollow.

“Harry was awesome out there especially that decision on the last,” reflected McIlroy. “I was ready to get in there and try to play that with a lob wedge and he was sort of like, ‘Let's take a step back, let's think about this, where's the best place you're hitting your third from.’

"So he sort of calmed me down, slowed me down a little bit and said, ‘Pal, let's just think about this.’ Ultimately we made the right decision, it's Harry and I's sixth win together and it's probably been our best one. Bay Hill back in 2018 was great because I hadn't won in a while, but this is even better just because Harry's been there every step of the way."

After McIlroy's win at The Players in 2019, he described Diamond as "one of the best caddies out here, if not the best."

It has not always been plain sailing for the pair, though, with Diamond coming in for a good deal of criticism following McIlroy's late collapse at the US Open in 2024. Some external parties were calling for McIlroy to move on from Diamond if he wanted to win another Major, with one particular bone of contention being a crucial club choice in the closing holes at Pinehurst No.2 which may have cost the Northern Irish duo dear.

Nevertheless, McIlroy stood firm and fiercely defended his best friend and caddie later down the line, calling out a couple of detractors by name. He said: “You know, it’s certainly unfair.

"Hank Haney has never been in that position. Smylie has been in that position once. I love Smylie, and he was out there with us on 18, but just because Harry is not as vocal or loud with his words as other caddies, it doesn’t mean that he doesn’t say anything and that he doesn’t do anything.

"I just wish that, you know, these guys that criticize when things don’t go my way, they never say anything good when things do go my way.”

“So where were they when I won Dubai earlier year, or Quail Hollow, or the two FedExCups that I’ve won with Harry, or the two Ryder Cups … or whatever? They are never there to say Harry did such a great job when I win, but they are always there to criticize when we don’t win.”

McIlroy went on to win his sixth Race To Dubai title later in the year before opening up 2025 with success at the Pebble Beach Pro-Am and The Players Championship. Heading into The Masters, McIlroy was World No.2 and playing some of the best golf he'd managed with Diamond as his looper.