Johnson said it was his best round in a long time. He posted 64, 70, 69 and 65 for a total of 268 and a two-stroke victory over hard-charging Nick Watney, who closed with a 64.
The Iowan and 10-time PGA Tour winner now heads to Atlanta with a chance to win it all. Moving up 23 spots thanks to his 16-under performance at Conway Farms, Johnson is fourth in the FedEx Cup points race.
Here's how things stand:
1. Tiger Woods (4,352)
2. Henrik Stenson (4,229)
3. Adam Scott (4,122)
4. Zach Johnson (3,843)
5. Matt Kuchar (3,330)
6. Steve Stricker (3,180)
7. Graham DeLaet (3,011)
8. Phil Mickelson (2,939)
9. Justin Rose (2,842)
10. Brandt Snedeker (2,726)
Any of the top five players can claim the $10 million FedEx Cup by winning this week's finale, the Tour Championship at East Lake Golf Club.
"I'm not sure I fully grasp it," Johnson said about his 10 wins in 10 seasons on the PGA Tour.
"The parity on the Tour and in the world is second to none. I'm just thankful it has been 10 years, and hopefully many more."
Source: Zach Johnson Is Golf Boss of Chicagoland