HONOLULU, 19 Jan, 2015 (AFP) - The 36-year-old American posted the biggest winning margin in the 50-year history of the event. He fired a seven-under 63 to finish at 23-under 257, nine shots in front of runner-up Scott Piercy.
He also won just a week after blowing a three-shot lead with five holes to play at the Hyundai Tournament of Champions in Maui.
"I really wanted to finish out the day today, which I didn't do last week," he said. "I kept grinding and making putts and that's what I did today."
In this event last year, Walker emerged from a five-way tie to shoot a closing round of 63 and beat Chris Kirk by one shot.
South Africa's Ernie Els was the last back-to-back winner of the Sony Open in 2004.
Walker shot four straight rounds in the 60s this week at the Waialae Country Club to finish the week at 23-under-par 257.
The victory is his fourth on the PGA Tour and his first since winning the AT&T National Pro-Am last season.
"Just more confidence, more comfortable," Walker said. "I've got good people. I've got a great trainer, Mark, a good coach in Butch and a great wife and kids. Things are good."
Piercy posted his second straight 66 to finish in sole possession of second place at 14-under 266. Harris English and Gary Woodland both fired three-under 67s, while Matt Kuchar fired a one-over 71 and the trio finished tied for third at 13-under 267.
Rory Sabbatini (63), Jerry Kelly (66), Brian Davis (67), Zac Blair (67), Max Homa (69), Shawn Stefani (68) and Justin Thomas (70) all ended tied for sixth at 12-under.
Walker entered the final round with a two-shot lead and then coasted out of the gate with seven straight pars followed by back to back birdies.
But he showed no mercy on the back nine, recording five birdies and four pars to complete the nine-stroke win.
Piercy shot a bogey-free round with birdies on one, two, 10 and 16, but there was no way he was going to overtake Walker.
The PGA Tour heads to the US mainland next week for the Humana Challenge near Palm Springs, California.
Leading final-round scores on Sunday in the $5.6 million USPGA Sony Open (USA unless noted, par-70):
257 - Jimmy Walker 66-66-62-63
266 - Scott Piercy 67-67-66-66
267 - Matt Kuchar 65-63-68-71, Gary Woodland 70-65-65-67, Harris English 66-69-65-67
268 - Jerry Kelly 73-62-67-66, Rory Sabbatini (RSA) 64-67-74-63, Brian Davis (ENG) 66-70-65-67, Shawn Stefani 69-66-65-68, Justin Thomas 67-61-70-70, Max Homa 69-67-63-69, Zac Blair 71-66-64-67
269 - Webb Simpson 62-66-72-69, Brian Harman 66-67-64-72, Russell Knox (SCO) 66-65-69-69, Daniel Berger 68-66-68-67
270 - Stuart Appleby (AUS) 68-69-67-66, Pat Perez 67-68-70-65, Ryan Palmer 69-63-69-69, Jason Day (AUS) 65-69-68-68, Colt Knost 70-68-66-66, Jason Kokrak 67-69-64-70, Daniel Summerhays 66-67-67-70, Russell Henley 72-64-67-67, Robert Streb 63-69-69-69
271 - Charles Howell 69-66-67-69, Chez Reavie 67-67-68-69, James Hahn 69-64-69-69, Chris Kirk 66-67-74-64