IRVING, 31 May 2015 (AFP) - The 31-year-old Aussie posted four birdies on the back nine to distance himself from the field and finish at 18-under-par 259.
This was his second win on the USPGA Tour, and his second victory in the state of Texas after claiming the Texas Open in San Antonio in 2014.
"We took some wedding pictures here at TPC so it is a special place and I get to take some more pictures here," said Bowditch, who married his wife at the Dallas area golf club in 2011.
Americans Charley Hoffman (65), Jimmy Walker (66) and Scott Pinckney (66) shared second place at 14-under. Both Hoffman and Walker tried to catch Bowditch but Walker posted two bogeys early on the back nine and Hoffman simply ran out of steam.
Zach Johnson fired a six-under 63 to seize fifth place at 13-under-par 264. Brandt Snedeker (64) and Jon Curran (68) tied for sixth at 12-under.
Dustin Johnson grabbed a share of the lead with a pair of early birdies, but he stumbled to a quadruple-bogey at the sixth which dropped him four back.
Johnson closed with an even-par 69 to end in a share of eighth at 11-under-par 266. He was joined there by 2012 champion Jason Dufner (66).
Leading final round scores at the PGA Tour's Byron Nelson event on the par-70 Four Seasons Resort course on Sunday.
259 - Steven Bowditch (AUS) 62-68-65-64
263 - Charley Hoffman 69-65-64-65, Jimmy Walker 64-66-67-66, Scott Pinckney 69-64-64-66
264 - Zach Johnson 69-64-68-63
265 - Brandt Snedeker 71-66-64-64, Jon Curran 67-63-67-68
266 - Jason Dufner 71-65-64-66, Dustin Johnson 67-68-62-69
267 - Cameron Percy (AUS) 67-64-68-68, Ryan Palmer 65-66-67-69, Nick Watney 67-65-70-65, Tony Finau 67-64-68-68, Colt Knost 68-65-66-68, Daniel Berger 72-65-64-66
268 - Kenny Perry 69-68-64-67, Gonzalo Fernandez-Castano (ESP) 70-68-67-63, John Merrick 66-67-69-66, Nicholas Thompson 70-67-66-65, Brooks Koepka 69-68-64-67, Zac Blair 69-64-66-69