The fifth-ranked Rose shot a 5-under 66 to defeat his Ryder Cup teammate and fellow Englishman by one stroke at the Antalya Club.
Rose, who won all of his five matches in the $5.2 million exhibition, birdied the opening hole on the Sultan Course and led the rest of the way against his fourth-ranked opponent.
Westwood birdied the 16th to get back to one behind before Rose sealed the match by holing a 20-foot putt for birdie at the 17th. It was a similar length to the putt he made at the same hole in his Ryder Cup singles victory last month against Phil Mickelson.
On Thursday, Rose chipped in at the 17th to beat Tiger Woods in the semifinals of the $5.2 million event, sponsored by Turkish Airlines.
"The 17th green has been really good to me this week, as I holed my second shot there yesterday and, of course, the 17th at Medinah turned around my match against Phil," Rose said. "But you have to be pleased to go through this whole week after winning all my five matches."
The paycheque is Rose's highest in his 14-year pro career and $560,000 more than his prize in capturing the 2011 BMW Championship.
"To not get beaten at all in the group stage and then to win the two finals is a great feeling and it's been a great week," he said. "My golf is just so consistent at the moment and the main thing is that I just don't have any skeletons in the closet, and I don't have that loose shot that is plaguing me all the time."
Westwood earned a check for $1 million for his efforts over three days.
"We both played well with just the slight difference on the greens," Westwood said. "Justin rolled some 20 footers, another crucial one at 17, while the longest putt I made was eight or nine feet on 16. So I left a lot of chances out there but that is the way it goes."
All eight players then participated in a Pro-Am. Turkish Golf President Ahmet Agaoglu was drawn to play alongside Woods.
Agaoglu was at the centre of controversy earlier in the week when he allegedly head-butted a journalist while trying to move him away from Woods on the opening tee.
Agaoglu was asked if he was nervous playing with Woods.
"I'm not nervous but what I want to do is make him nervous, as I will own him for the next four or five hours," he said with a smile. "I paid for him to be here in Turkey, so he's my property this afternoon."
Woods was reportedly paid a $3 million appearance fee to compete in Turkey. He also earned $600,000 as a semifinalist.