The 25-year-old former Stanford University student knew of his spot only late on Sunday evening when first Rasmus Hojgaard and then Alex Smalley bogeyed the final hole of the Genesis Scottish Open.
It handed Wu, 293rd in the world at the time, the third of three places on offer as part of The Open Qualifying Series even though he finished joint-sixth.
That was because four of the players ahead of him were already exempt, as were Matt Fitzpatrick and Cameron Tringale, who like him finished three-under-par.
Three years ago, when still an amateur, Wu won the Final Qualifying event at Fairmont St Andrews for a championship debut at Royal Portrush only a month after he was joint 35th in his first US Open.
Helped Stanford win the NCAA Championship in his senior year before being presented with his graduation diploma as he came off the 18th green at Pebble Beach after playing with Dustin Johnson in the final round.
Turned professional later the same year after playing in a winning Walker Cup team at Hoylake and in August 2020 won the Korn Ferry Tour Championship. Has had second and third place finishes on the PGA Tour this season.