The Northern Irishman, who has struggled on each and every Sunday on which he has been in contention since his last Tour win at Bay Hill in March 2018, went into the final day a shot back from the overnight leader, Jon Rahm.
He started the day level with Tommy Fleetwood, who got off to a nervous start as he tried to claim his first PGA Tour title.
Fleetwood began the final round a shot off the lead held by playing partner Jon Rahm, but the Ryder Cup team-mates both three-putted the opening hole from long range.
Fleetwood also three-putted the par-five second from just short of the green, albeit for a par, to remain a shot behind Rahm and Rory McIlroy, who had parred his first three holes.
Former world number one Tiger Woods had already completed a closing 69, his best round of the week, to end on six under par.
McIlroy's hopes suffered a major blow when he found the water with his approach to the fourth to run up a double-bogey six.
However, with Rahm dropping a shot on the same hole after hitting a spectator in the chest with his second shot, a birdie from McIlroy on the sixth briefly took him back into a share of the lead before he promptly bogeyed the next.
With the overnight leaders struggling, Mexico's Abraham Ancer and American Ollie Schniederjans took advantage to move into a tie for the lead on 13 under alongside Rahm and Fleetwood, with 19 players separated by just three shots.
Rahm steadied the ship with a birdie on the sixth and another on the eighth took him back into the outright lead on 14 under.
However, former Ryder Cup captain Jim Furyk started the back nine with birdies on the 10th and 11th to join Rahm at the head of affairs.
The 48-year-old is looking to become the oldest ever winner of the Players Championship. Furyk is less than a month older than 2005 champion Fred Funk.
McIlroy made it a three-way tie for the lead with birdies on the ninth and 11th, but some even better scoring was coming from England's Eddie Pepperell.
On his debut in the event, Pepperell birdied the seventh, ninth, 11th, 13th, 15th, 16th and 17th, the latter a double-breaking putt from all of 50 feet.
That took Pepperell into a share of the lead on 14 under and with the chance to set a testing clubhouse target.
Pepperell's putt on 17 was amazingly eclipsed by Jhonattan Vegas, who holed from 70 feet and then hit a brilliant approach to five feet on the last.
However, Vegas missed the birdie chance and had to settle for a 66, matching Pepperell's score and leaving the pair tied for the clubhouse lead on 14 under.
McIlroy also dropped back to 14 under with a bogey on the 14th and birdies from Rahm on the 13th and Furyk on the 16th made it a five-way tie.
Furyk was agonisingly close to another birdie on the 17th but made no mistake on the last, hitting a stunning approach to three feet and converting the putt.
That set the new target on 15 under and McIlroy quickly matched it with a birdie on the 15th after a superb shot from a fairway bunker.
McIlroy took advantage of a 347-yard drive on the par-five 16th to set up a two-putt birdie and take a one-shot lead down the last two holes.
Fleetwood moved to within two shots of the lead with an eagle on the 16th before his ball found the water, via the sleepers, on the 17th.
Additional reporting by the Press Association.