Gay closed with a 9-under 63 on PGA West’s Arnold Palmer Private Course to match Howell and Swedish rookie David Lingmerth at 25-under 263.
Howell shot a 64, and Lingmerth had a 62. Stallings, five strokes ahead entering the round, bogeyed the final hole for a 70 to miss the playoff by a stroke.
The 41-year-old Gay began the round six strokes behind Stallings.
“The thoughts were, ‘Just be aggressive, shoot as low as you can,’” Gay said. “I knew Scott was five ahead. Even with a great round, a really low round, it would be tough to catch him, if at all. I played great on the front, just tried to stay aggressive and shoot low.”
Gay and Howell opened the playoff with birdies on the par-5 18th, and Lingmerth dropped out with a bogey after hitting his approach into the left-side water.
Gay won on the par-4 10th, hitting a perfect drive and putting his 9-iron second shot in good position below the hole. Howell drove into the right rough, hit his second into the back bunker, blasted out to 15 feet and two-putted for bogey.
“I’m still in a little bit of shock,” Gay said. “It kind of happened so fast there at the end the way things went down.
“Last year was a struggle. It was a long year, a lot of work. I just wanted to come out this year kind of refocused, recharged, and believing in myself.”
Howell tied for second a week after opening the season with a third-place tie in Hawaii in the Sony Open.
He won the last of his two tour titles in 2007.
“Anybody that says that that golf is fun or whatever, has really not done it for a living,” Howell said.
“I would never characterize this as fun. It’s different than that. It’s awfully challenging mentally and the chances to win are what we want.”
After birdieing nine of the first 13 holes, Gay finished regulation with five straight pars. On the 18th, he missed the green to the right and failed to hole an 8-foot birdie try.
“I felt like I gave one back with a par on 18 there,” Gay said. “Was fortunate enough to feel like I had a second chance with two guys left that didn’t birdie the hole. Kind of a second chance, if you will. I was happy to be in the playoff at that point.”
Given that second chance, he outlasted Howell for his fourth PGA Tour title. He won the Verizon Heritage and St. Jude Classic in 2009 and the Mayakoba Golf Classic in 2008.
Playing in the second-to-last group, Howell had a chance to pull ahead on the final hole of regulation, but left his approach about 85 feet short and three-putted for par. His 5-foot birdie try made a left turn inches from hole.
“Quite honestly, going into the day, I didn’t really think that anybody had a chance apart from Scott,” Howell said.
Stallings hit a 315-yard drive on the 18th to set up a 6-iron approach from 220 yards. The ball landed in the left rough, bounced into rocks and finished in the water. After a penalty drop, he chipped to 10 feet and missed his par try.
“I felt great. There wasn’t any nerves or anything like that going into it,” Stallings said.
“Just hit a bad shot. Same thing that happened on 14. Felt like I made a good swing, just ball came off a little right and got a bad kick and went in the water.
“Coming down the stretch on the 72nd hole, you can’t make mistakes like that. And it stinks, but it’s something that I’ll definitely learn from.”
The two-time tour winner saved par on the par-5 14th after hitting his into the All-American Canal on the right side, but dropped a stroke on the par-4 16th after his 4-iron tee shot went farther than he expected and ended up in the lip of a fairway bunker.
“You’re going to have your good days and your bad days, but if you live and die with every shot out there, your career is not going to last very long out there,” Stallings said.
Making his second career PGA Tour start, Lingmerth hit his 4-iron approach way left into the water in the playoff. He had an awkward stance on the shot with the ball above his feet.
“I didn’t feel that comfortable over it, obviously,” Lingmerth said. “I just hit a bad shot. I wish I could have it back. ... I was fortunate to have a chance here, and I’m sure I’ll learn from it looking forward to the next opportunity.”
Phil Mickelson had a 66 to tie for 37th at 17 under in his season debut. He was making his start since the HSBC Champions in early November in China.
“I was rusty starting the year,” Mickelson said. “I had a great four days here where I can work on my game with perfect weather and wonderful golf courses, where I could build some momentum. Heading into San Diego, I feel a lot more confident in my game. I feel like I’m starting to play well, hit some putts on line.”
DIVOTS: James Hahn eagled the last for a 62 to tie for fourth with Stallings. ... Russell Henley, the Sony Open winner last week in his first start as a PGA Tour member, tied for 56th at 15 under after a 69. ... FedEx Cup champion Brandt Snedeker shot a 67 to tie for 23rd at 19 under. He was the highest-ranked player in the field at No. 8.
x-Brian Gay (500), $1,008,000 67q-66n-67p-63p—263
David Lingmerth (245), $492,800 68q-64n-69p-62p—263
Charles Howell III (245), $492,800 67q-65n-67p-64p—263
James Hahn (123), $246,400 63p-67q-72n-62p—264
Scott Stallings (123), $246,400 66p-65q-63n-70p—264
Nicholas Thompson (95), $194,600 69q-66n-66p-64p—265
Ryan Palmer (95), $194,600 65p-69q-66n-65p—265
Kevin Chappell (83), $168,000 68q-69n-67p-62p—266
Jason Kokrak (83), $168,000 63q-69n-69p-65p—266
Richard H. Lee (64), $124,133 66n-65p-70q-66p—267
Billy Horschel (64), $124,133 67n-68p-65q-67p—267
Kevin Streelman (64), $124,133 69n-65p-66q-67p—267
Brian Stuard (64), $124,133 71p-67q-62n-67p—267
Charley Hoffman (64), $124,133 65n-67p-67q-68p—267
Stewart Cink (64), $124,133 66q-67n-66p-68p—267
Robert Streb (52), $78,560 67n-69p-68q-64p—268
Matt Kuchar (52), $78,560 70q-64n-69p-65p—268
Bryce Molder (52), $78,560 66p-68q-68n-66p—268
Ricky Barnes (52), $78,560 65q-68n-69p-66p—268
Robert Garrigus (52), $78,560 66p-67q-69n-66p—268
Bob Estes (52), $78,560 69q-69n-67p-63p—268
John Rollins (52), $78,560 70p-65q-64n-69p—268
Matt Jones (47), $51,520 68n-68p-69q-64p—269
Brandt Snedeker (47), $51,520 67q-68n-67p-67p—269
Jimmy Walker (47), $51,520 66p-70q-66n-67p—269
Zach Johnson (47), $51,520 66p-66q-70n-67p—269
Tom Gillis (40), $35,728 69p-66q-69n-66p—270
Fabian Gomez (40), $35,728 69q-67n-67p-67p—270
Luke Guthrie (40), $35,728 73q-67n-64p-66p—270
Geoff Ogilvy (40), $35,728 70q-65n-70p-65p—270
Aaron Baddeley (40), $35,728 64p-68q-70n-68p—270
Bo Van Pelt (40), $35,728 66n-68p-68q-68p—270
Daniel Summerhays (40), $35,728 65n-68p-69q-68p—270
Jeff Overton (40), $35,728 69p-71q-66n-64p—270
Kevin Stadler (40), $35,728 66q-66n-68p-70p—270
Sang-Moon Bae (40), $35,728 67p-69q-64n-70p—270
Justin Hicks (30), $22,400 69p-69q-65n-68p—271
Johnson Wagner (30), $22,400 66n-70p-67q-68p—271
Doug LaBelle II (30), $22,400 64n-70p-70q-67p—271
Stephen Ames (30), $22,400 67p-68q-68n-68p—271
Cameron Tringale (30), $22,400 65n-72p-66q-68p—271
Justin Leonard (30), $22,400 67p-69q-67n-68p—271
Bud Cauley (30), $22,400 70n-63p-72q-66p—271
Phil Mickelson (30), $22,400 72q-67n-66p-66p—271
Lee Williams (30), $22,400 67q-65n-68p-71p—271
Roberto Castro (30), $22,400 63n-67p-69q-72p—271
Carl Pettersson (20), $14,062 68n-66p-69q-69p—272
Steven Bowditch (20), $14,062 71n-65p-67q-69p—272
Brendon de Jonge (20), $14,062 69q-69n-66p-68p—272
Jeff Maggert (20), $14,062 65n-72p-67q-68p—272
Martin Laird (20), $14,062 69n-69p-66q-68p—272
Greg Chalmers (20), $14,062 64n-68p-71q-69p—272
Jerry Kelly (20), $14,062 65n-71p-69q-67p—272
Camilo Villegas (20), $14,062 71q-67n-67p-67p—272
Lucas Glover (20), $14,062 71p-69q-65n-67p—272
Russell Henley (12), $12,432 64n-69p-71q-69p—273
William McGirt (12), $12,432 68p-66q-70n-69p—273
Darron Stiles (12), $12,432 66p-65q-72n-70p—273
D.J. Trahan (12), $12,432 69p-68q-68n-68p—273
Brendan Steele (12), $12,432 72p-70q-64n-67p—273
Tag Ridings (12), $12,432 67n-71p-68q-67p—273
Ross Fisher (12), $12,432 74q-65n-67p-67p—273
D.A. Points (8), $11,928 67q-69n-69p-69p—274
Colt Knost (8), $11,928 68q-67n-71p-68p—274
Harris English (3), $11,424 67n-69p-67q-72p—275
Brad Fritsch (3), $11,424 69q-65n-71p-70p—275
Stuart Appleby (3), $11,424 67q-70n-68p-70p—275
Luke List (3), $11,424 70n-66p-69q-70p—275
Boo Weekley (3), $11,424 68q-67n-71p-69p—275
John Senden (3), $11,424 72p-66q-68n-69p—275
Graham DeLaet (3), $11,424 71p-70q-65n-69p—275
Alistair Presnell (1), $10,808 68p-70q-65n-73p—276
David Mathis (1), $10,808 70q-66n-70p-70p—276
Shawn Stefani (1), $10,808 68q-69n-69p-70p—276
D.H. Lee (1), $10,808 70q-66n-70p-70p—276
Michael Bradley (1), $10,416 65n-69p-72q-71p—277
Jason Bohn (1), $10,416 70n-69p-67q-71p—277
Charlie Wi (1), $10,416 72q-64n-70p-71p—277
Ben Kohles (1), $10,136 68p-68q-66n-76p—278
David Toms (1), $10,136 75p-67q-64n-72p—278
Greg Owen (1), $9,968 72q-65n-68p-75p—280