Yuta Ikeda secured one of four qualification places for The 148th Open after winning the Mizuno Open in Japan.
Ikeda posted a one-under 71 at Royal Golf Club to claim a one-shot victory over Chan Kim and register a 21st career win on the Japan Golf Tour.
Kim also booked his place at Royal Portrush for the final major of the year, with Sang-Hyun Park and Gunn Charoenku - who both finished in a share of third - taking the other two spots.
"I am very happy to have qualified for The Open thanks to this victory," Ikeda said. "I was worried I might not be able to play in it this year, so it is great to have the opportunity to play on the big stage again."
Ikeda makes his eighth appearance at The Open and Park returns for a second time in as many years, while Kim will play in the event for the first time since a tied-11th finish at Royal Birkdale in 2017 and Charoenkul makes his debut.
"I had a chance to qualify at the SMBC Singapore Open and the Diamond Cup but I just missed out, so I am very happy to have qualified in Japan," Charoenkul said.
The next event in The Open Qualifying Series will be the RBC Canadian Open from June 6-9, live on Sky Sports, where three more places will be up for grabs.