Irwin, the lone player in the field to post all three rounds in the 60s, closed with a 4-under 68 to secure his third victory of the season and the 32nd of his dominating Senior Tour career.
Irwin, who extended his lead to three over Lee Trevino on the all-time Senior Tour win list, captured his fourth official title in Hawaii as a member of the 50-and-over circuit. He also won the unofficial Senior Skins Game in the Aloha State in 1999 and 2001.
The most recent of Irwin's official Hawaiian wins prior to this week's came at the 2000 Kaanapali Classic in Maui, the event that was replaced on the 2001 schedule by the Turtle Bay Championship.
'It's been a wonderful run in Hawaii,' said Irwin, who also won the 1981 Hawaiian Open while a member of the PGA Tour.
This marked the sixth straight season in which Irwin has earned at least three Senior Tour victories. He claimed a pair of titles in only 12 starts in his rookie year of 1995.
Irwin was three shots up at the turn but saw his lead trimmed to one after Jacobs rolled in a five-foot birdie putt at the 12th hole and six-footer at the 14th.
But Irwin answered the challenge down the stretch, knocking a pitching wedge from 105 yards to within three feet for birdie at the 452-yard, par-4 17th.
Jacobs' last gasp came at the 539-yard, par-5 18th, where he carried his second shot 262 yards over water to the green. Left with an eagle putt of more than 70 feet, Jacobs slightly misread his stroke and his ball finished six feet left of the hole.
Meanwhile, Irwin laid up with a 5-iron then wedged his third shot to eight feet. Two strokes down and inside of Irwin, Jacobs graciously went first but missed his birdie try and tapped in for a par. Irwin then sank his putt for a final birdie and the winning total of 11-under-par 205.
Jacobs, a three-time Senior Tour winner, had a 69 to finish at 8-under 208. It was his best showing of the 2001 season and his seventh career second-place finish.
Two shots back of Irwin at the start of the day, Jacobs suddenly found himself four off the pace after Irwin birdied the first and third holes to climb to 9-under par. Jacobs, who moved to 6-under with an 18-foot birdie putt at the fifth hole, drew within one of the lead following a two-shot swing at the par-4 seventh.
Irwin's bogey at No. 7 was the result of a three-putt from 20 feet, while Jacobs picked up a birdie after hitting a sand wedge to three feet.
The roles were reversed at the par-5 9t however, as Jacobs drove his ball in the water off the tee and wound up taking a bogey. He was down three again after Irwin sank a 12-foot birdie to return to minus-nine.
'The ninth hole was the difference,' Jacobs said. 'If I could have birdied that, I could have caught Hale. I had my chances today, but you've got to shoot better than 69 to beat Hale Irwin.'
Terry Mauney, a first-round co-leader with Jacobs, carded a 67 to finish in third place with Senior Tour money leader Allen Doyle (68) at 6-under 210. Doyle registered his 24th top-10 finish of the year, leaving him just two top-10s shy of Trevino's all-time record of 26 with three official events remaining on the 2001 schedule.
Mike McCullough (67) and Hubert Green (72) tied for fifth at 5-under-par, one shot ahead of Bruce Summerhays (68), Isao Aoki (70) and Walter Hall (70).
Jay Sigel, who opened with a 6-over 78 on Friday, finished alone in 10th place after closing with a bogey-free 65 -- the low round of the tournament.
Click Here for Full-Field Scores from the Turtle Bay Championship.