[10] After further issues that resulted in his dismissal from the team,[11] he then left Georgia and enrolled at Augusta State University, where he majored in business.

[17] On August 18, Reed became the 12th first-time PGA Tour winner of the year with his victory at the Wyndham Championship in a playoff against Jordan Spieth.

The previous record was 25-under-par, set by Gay Brewer at the 1967 Pensacola Open and tied by Ernie Els at the 2003 Mercedes Championships, Pat Perez at the 2009 Bob Hope Classic (the previous name of the Humana event) and Steve Stricker at the 2010 John Deere Classic.

[23] On March 9, Reed won the WGC-Cadillac Championship at Trump National Doral in Miami, Florida.

Reed became only the fifth golfer to earn three PGA Tour wins before his 24th birthday since 1990, joining Tiger Woods, Phil Mickelson, Rory McIlroy and Sergio García.

Reed is the youngest winner of a WGC event, and the victory also moved him to 20th in the Official World Golf Ranking.

[26] On January 12, Reed won his fourth PGA Tour title at the Hyundai Tournament of Champions by defeating Jimmy Walker in a sudden death playoff.

[27] He became just the fourth player in the last two decades to win four times on the PGA Tour before his 25th birthday, the other three were Tiger Woods, Rory McIlroy, and Sergio García.

On August 28, Reed won the first FedEx Cup playoff event, The Barclays played at Bethpage Black.

The win vaulted Reed to the top of the FedEx Cup standings from 7th position ahead of Jason Day.

After the second FedEx Cup playoff event, the Deutsche Bank Championship, Reed extended his lead to 556 points over Day, with a top-10 finish.

[35] On the final day of the PGA Championship, Reed had three birdies on the back to get to within a shot of the lead, but bogeyed the 18th after finding a fairway bunker off the tee and tied for second, two strokes behind winner Justin Thomas.

[37] On Sunday April 8, 2018, McIlroy faltered and Reed fought off the final round comeback bids of Jordan Spieth and Rickie Fowler to win the green jacket, shooting 71 (−1) for a tournament total of 273 (−15).

Late on Sunday September 30, 2018, Karen Crouse of The New York Times published an article with quotes from Reed.

In the article, Reed questioned Jordan Spieth and U.S. captain Jim Furyk about the breakup of the previously successful Reed-Spieth Ryder Cup pairing.

Reed also described the Ryder Cup pairing decision-making process as "a buddy system" that ignores the input of all but a few select players.

[40] In August 2019, Reed won the Northern Trust at Liberty National Golf Club near New York City.

[42] In January, Reed won the Farmers Insurance Open at Torrey Pines Golf Course in La Jolla, California.

[43] In August, Reed was admitted to hospital having been diagnosed with bilateral pneumonia which forced him to miss the first two FedEx Cup Playoff events.

He returned to action in early September at the Tour Championship in the hope that by proving his fitness he might gain a captain's pick for the Ryder Cup; he finished the tournament in 25th place.

When the 12-man USA team was announced by Steve Stricker the following week, Reed, who had finished 11th in the points standings, was not selected.

[49][50] In January 2021, during the third round of the Farmers Insurance Open, Reed obtained a free relief for an embedded ball in the rough on the tenth hole.

[53][54] In August 2022, it was reported that a defamation lawsuit had been filed on Reed's behalf, alleging that Brandel Chamblee and his employers, Golf Channel, had "conspired... for and with the PGA Tour" to defame Reed by intentionally misreporting through omission and falsification of various facts, resulting in harm to his reputation and causing him to experience abuse.

[57] In January 2024, the court concluded Reed filed the lawsuit to stifle free speech, and ordered him to pay the defendants' legal fees and costs.

1Cancelled due to COVID-19 pandemic QF, R16, R32, R64 = Round in which player lost in match play NT = no tournament "T" = tied Note that the Championship and Invitational were discontinued from 2022.