Jim "Bones" Mackay

His nickname, "Bones", was created in 1990 when PGA Tour player Fred Couples couldn't remember the name of the lanky, 6-foot 4-inch Mackay.

[1][2] Mackay was born in Redhill, Surrey, England; his family moved to New Smyrna Beach, Florida, when he was seven years old.

[1] Of their long and close relationship, Mickelson has been quoted as saying "Bones is the only guy on the golf course that wants me to play well, so why am I going to sit there and berate him and treat him poorly?

[6] On September 30, 2021, Mackay announced he was returning to the bag as full-time caddie for Justin Thomas.

[7] On April 3, 2024, Thomas announced that he and Mackay were parting ways, a week before the 2024 Masters Tournament.