Lee, who was a breakthrough champion back in 2021 in this event, clung on doggedly in pursuit of Kim on Sunday (Monday AEST) at the Renaissance Club at North Berwick, only to fall two shots short as the Korean played bogey-free during a tight run-in to the finish and closed with a decisive six-under par 64.
Kim ended up celebrating his first PGA Tour title since 2023, finishing on a 17-under-par 263, with Lee's last-round 67 proving not quite enough.
Still, the runner's up spot - not to mention the second-prize cheque of 861,500 Euros ($A1.4 million) - was enough to give the 27-year-old from Perth a real boost going into the season's final major, the British Open, which starts at Royal Birkdale on Thursday.
Lee's hopes finally disappeared on the last fairway when he watched Kim, up ahead, sink the four-foot par putt on the 18th to effectively shut the door.
It meant he had to hole out from the fairway just to force a play-off, but he was still happy to end with the par that earned him second-place outright on 15-under, ahead of a quartet on 13 under - Matt Fitzpatrick (69), Robert MacIntyre (69), Keita Nakajima (67) and Johnny Keefer (67).
It was a big finish for Keefer, the Korn Ferry Tour player of the year in 2025 who earned one of three spots to the Open next week along with American Michael Thorbjornsen and Frenchman Victor Perez.
Kim, who reached as high as No.11 in the world at just 21 when he won in Las Vegas nearly three years ago, reckoned the key shot was the blow from 203 yards to six feet on the par-four 16th that gave him the necessary breathing space from Lee.
"That second shot might be one of the best shots I've hit in my career so far," he said.
On a long final day after the third round was interrupted by fog, Rory McIlroy fell short after getting within one shot of the lead. He wound up with a 64 to tie for seventh.
Among the other Australians on view, Cam Davis ended with a 67 to finish on seven under, tied for 21st, while Karl Vilips' 73 ensured he finished tied for 30th on five-under.
History-maker Adam Scott, tuning up for his 101st consecutive major championship at Birkdale, ended up in joint-66th place on two-over after a final-round 69.
With agencies
