KUALA LUMPUR, 2 Nov, 2014 (AFP) - The 31-year-old American achieved his first victory of the year with a five-under-par 67 to finish on 17-under 271.
Moore fended off competition from Gary Woodland and Kevin Na of the United States and Spain's Sergio Garcia, who all ended the tournament on 14-under 274.
Woodland posted an identical 67 with six birdies, but a bogey on the final hole meant he was left as bridesmaid to Moore again.
England's Lee Westwood, who won the Malaysian Open in April, was unable to capitalise on a low 65 in the second round, ending the tournament eight shots behind Moore.
Moore, who employs an unorthodox swing, described his finish as "incredible".
"I always tell myself that I’m a closer, that’s what I play golf for and what I’m out here for," he said.
"Gary had a fantastic weekend. I saw him charging up there today, and that motivated me to just keep making birdies. He was playing some good golf and must have been feeling pretty good. But in my mind I knew if I got to 18, I would have it," Moore added.
Moore becomes the first person successfully to defend a title on tour since Tiger Woods at the Arnold Palmer Invitational, in 2012 and 2013.
Na and Garcia saw their challenge derailed after a double bogey on the back-nine, with the former appearing furious with himself after the error on the 17th.
"I was a bit frustrated. A camera went off and you probably saw me shake a finger to say no cameras. I never regrouped from that and it’s my fault for hitting a bad putt that late in the day. But Ryan played fantastic and hats off to him, he deserves it," Na said.
Moore pockets $1.26 million and 500 FedExCup points for his win in the tournament, which is co-sanctioned by the PGA Tour and the Asian Tour.
Final round scores on Sunday in the $7 million CIMB Classic at Kuala Lumpur Golf and Country Club: (Par 72)
271 - Ryan Moore (USA) 68-69-67-67
274 - Gary Woodland (USA) 71-70-66-67, Kevin Na (USA) 69-68-67-70, Sergio Garcia (ESP) 69-68-68-69
276 - Cameron Smith (AUS) 70-69-69-68, Bae Sang-moon (KOR) 71-68-68-69
277 - John Senden (AUS) 72-68-69-68
278 - Rory Sabbatini (RSA) 70-72-70-66, Davis Love III (USA) 68-71-71-68, Prom Meesawat (THA) 68-71-70-69, Angelo Que (PHI) 67-72-69-70, Billy Hurley III (USA) 67-67-71-73
279 - Jonas Blixt (SWE) 69-69-75-66, Danny Lee (NZL) 69-69-73-68, Brian Stuard (USA) 67-72-72-68, Lee Westwood (ENG) 72-65-74-68, Kevin Chappell (USA) 69-68-70-72, Brendon de Jonge (ZIM) 70-73-65-71
280 - Scott Stallings (USA) 69-76-67-68, Charl Schwartzel (RSA) 74-70-68-68