Staked to a five-shot lead, Leishman made back-to-back birdies late in the final round Sunday to put away the final challenge, then closed with a birdie for a 4-under 67 to set the tournament record.
The five-shot victory sends him to East Lake next week for the Tour Championship with a clear shot at winning the FedEx Cup and the $10 million bonus.
Leishman finished at 23-under 261, breaking the 72-hole tournament record previously set by Tiger Woods in 2007.
The drama was in the race for the top 30 in the FedEx Cup. PGA Tour rookies Xander Schauffele and Patrick Cantlay made key birdies late to get to East Lake.
