Bowditch, pictured in a performance golf shirt during the final round on Sunday, won the Texas-based AT&T Byron Nelson event by four strokes.
Ironically, the TPC Four Seasons venue was also the setting for his 2011 wedding to wife Amanda. Bowditch told the PGA Tour website that the place is "very special" to him, making the win truly "unbelievable".
The 31-year-old Australian's last-round 64, including seven birdies, secured a reward for four-day consistency on 18-under.
Scott Pinckney, Jimmy Walker and Charley Hoffman finished joint second on 14-under, shooting last rounds of 66, 66 and 65 respectively.
Jordan Spieth left recent form behind him, trailing by 11 shots.
But the honours went to Bowditch, who went into the fourth day with a handy two-stroke buffer.