Smith completed his first tour title at 19-under-par 269.
Scott Hawley closed with a 3-under 69 to finish at 16-under-par 272. Spencer Levin, who shared second place at the San Jose International Open, carded a final-round 66 to end alone in third at minus-14.
Taylor Wood (68) and Jose Trauwitz (71) shared fourth place at 12-under-par 276 at El Cid Golf & Country Club.
Smith was steady on the front nine with birdies on two and eight to make the turn at 16 under. He carded his third birdie at the par-4 10th.
The Californian converted back-to-back birdie efforts from the 13th to climb to 19-under. Smith dropped a shot at the 16th, but came right back to birdie No. 17 from 25 feet out for the three-stroke win.
'Once I made that, I said to myself 'I think you just won a golf tournament',' Smith admitted. 'I'm feeling pretty darn good after this one. I think I've been ready to win for a while and I finally got it done. Hopefully this will open a door for me.'
Adam Bland, Graham Delaet, Steve Friesen, Michael Mezei and Paulo Pinto shared sixth place at 11-under-par 277.