Two strokes behind the pacesetting Mallinger overnight, rookie Blixt fired a three-under-par 68 to break clear of a tightly bunched leaderboard on a sun-splashed afternoon at CordeValle Golf Club.
The red-shirted Swede snatched the outright lead when he sank a seven-foot birdie putt at the driveable par-four 17th after over-hitting the green off the tee, then safely parred the last to finish at 16-under 268.
Blixt pumped his right fist in delight after sinking a four-footer to claim his first victory on the US circuit, before being soaked in champagne as he was embraced by friends and family on the 18th green.
"It's unbelievable," the 28-year-old Swede, who finished third at last week's Las Vegas Open, told Golf Channel after becoming the third rookie to triumph on the 2012 US Tour. "I have no words right now.
"This is the biggest dream I ever had. It's been the greatest two weeks I have ever had on tour."
Blixt, who was sidelined for two months earlier this season because of a rib injury, said having friends and family with him over the past fortnight had helped him stay ultra relaxed.
"I haven't thought about golf after rounds," he added with a grin. "I always practise after rounds and I haven't done that in these two weeks either. It's crazy, just crazy."
American Mallinger, like Blixt bidding for a maiden title on the tour, bogeyed five of the first nine holes on the way to a 72 and a tie for fourth at 14 under with compatriot Jimmy Walker (62), Fiji's Vijay Singh (68) and Brazil's Alexandre Rocha (68).
Veteran Tim Petrovic closed with a sparkling 64 to share second place with fellow American Jason Kokrak (68) in the second of four events in the US Tour's Fall Series.
For much of the afternoon at CordeValle, a playoff seemed to be on the cards and four players - Petrovic, Rocha, Blixt and Walker - were tied for the lead late in the final round.
Petrovic, whose only US Tour victory came at the 2005 New Orleans Classic, edged one stroke clear when he chipped in to birdie the par-five 15th before faltering with a bogey at the par-three 16th after being bunkered off the tee.
However, he regained a one-shot cushion with a birdie at the par-four 17th where he drove the green and two-putted, and narrowly missed sinking a 25-footer at the last.
"My hands were shaking coming off the last hole I was so pumped up," the 46-year-old Petrovic smiled. "The putter felt really good this week and I drove the ball really good today."
Blixt joined Petrovic at the top with a birdie at the par-five 15th, where he was just short of the green in two and chipped up to nine feet, and Kokrak made it a three-way tie by draining a 15-foot eagle putt at the 17th.
However, the tournament was effectively decided when Blixt birdied the 17th after his chip from greenside rough hit the flagstick for his ball to settle seven feet past the cup.
After coolly sinking that putt, the Swede parred the last to secure victory and earn a two-year exemption on the US Tour.