GREENSBORO, N.C. — The last five weeks feels like three months to 20-year-old Joohyung “Tom” Kim, and for good reason. The South Korean kid who named himself after a cartoon train is on the fast track.

He got a rare PGA Tour start in the Scottish Open because of his standing on a Korean tour points list, hopeful of doing well enough to get a shot at the Korn Ferry Tour finals.

Now he’s a PGA Tour winner who is No. 21 in the world and headed to the FedEx Cup playoffs, and he can probably count on a spot with the International team at the Presidents Cup.

All aboard with Tom the Train!

“It’s been a crazy month,” Kim said.

He announced his arrival on the PGA Tour at the Wyndham Championship, where he began the tournament with a quadruple-bogey 8 and finished it with a 9-under 61 for a five-shot victory.

“I’m really, really happy for Tom,” said Sungjae Im, who completed the rain-delayed third round Sunday morning with a one-shot lead and couldn’t keep up with Kim, because no one could. Kim shot 27 on the front nine that left everyone in his wake.

“He’s a great kid and to come out here and to win on tour as a nonmember and secure your card is really not an easy task and he achieved that,” Im said.

Kim, who turned 20 in June, is the second-youngest winner on the PGA Tour since World War II. Jordan Spieth was two weeks away from turning 20 when he won the 2013 John Deere Classic.

The victory gave Kim instant membership on the PGA Tour, making him eligible for the FedEx Cup playoffs that start next week. He is No. 34, assured of playing two postseason events and with a reasonable shot at getting to the finale at East Lake.

Im had a 68 and tied for second along with John Huh (67).

Kim spent his developmental years in the Philippines and in Australia. He already had won three times on the Asian Development Tour and once in Korea before making his American debut at age 18 in the 2020 PGA Championship at Harding Park.

As for the name? As a young boy, he was a big fan of Thomas the Tank Engine in the TV series “Thomas & Friends.”

“You’re supposed to let your parents name yourself and I was like, ‘Nope, I’m to name myself Thomas.’ I loved the show as a kid. I haven’t watched it or anything, but apparently I really loved the train.”

The other option — he was a big “Toy Story” fan — would have been Buzz Lightyear. That would have worked. The kid is creating quite the buzz, and he’s light years ahead of others his age.

Only Rory McIlroy and Sergio Garcia were younger when they reached as high as No. 21 in the world ranking.

Kim finished third in the Scottish Open, the first time it was co-sanctioned by the PGA Tour, and his goal was to get enough FedEx Cup points to finish equal to the top 200 so he could earn his card through a series of Korn Ferry Tour events late in the summer.

He earned special temporary PGA Tour membership when he made the cut at the British Open. He secured a PGA Tour card last week with a seventh-place finish in the Rocket Mortgage Classic. The stress gone, not even an opening quadruple bogey rattled him.

“It’s been a five-week stretch for me, but it feels like three months,” Kim said. “Yeah, it’s been a hectic month and a lot of things have changed, for sure.”

He finished at 20-under 260.

It was plenty stressful for others, even those who weren’t playing.

The heartbreak belonged to Justin Lower, who was poised to move into the top 125 in the FedEx Cup to reach the postseason and secure a full card for next season.

But on the final hole, Lower hit his 60-foot birdie putt a little too firm. That left him a 6-foot par putt that would have put him inside the top 125. He missed it to the right and was wiping away tears as he walked off the green.

“I don’t really know what I’m thinking. It sucks to come up this short,” Lower said. “Obviously had some help with the LIV guys and whatnot — I don’t even know if I’m allowed to say that. But I don’t know. There’s positives. But right now, it just flat out sucks.”

The tour has suspended players who signed on with Saudi-funded LIV Golf, and they did not count toward the top 125 in the FedEx Cup. Lower was the equivalent of No. 128 going into the final event of the regular season.

Rickie Fowler looked to be out of luck when he missed the cut on Friday at No. 123. But enough players faded on the weekend that Fowler gets to extend his season for at least another week at the FedEx St. Jude Championship next week.