Stadler shot a closing three-under-par 69 to finish on 20 under par for the tournament, edging out O’Hern by two shots.
The 26-year-old teed off on the par-five 18th needing a birdie to win the event and a brilliant second shot to the green left the American a simple one-foot putt to claim the biggest title of his career.
Stadler suffered a slight lapse on the front nine, registering three straight bogeys from the fifth hole, but he offset those with four birdies and his solitary eagle to claim the $490,000 first prize.
O’Hern completed a round of 68 to finish two shots clear of his compatriots Robert Allenby and Richard Green.
South Korea’s K.J. Choi was a further shot back in fifth place with defending champion Adam Scott of Australia registering a sixth-place finish after a final round 69.
Leading final round scores:
268 — Kevin Stadler (US) 64, 69, 66, 69.
270 — Nick O’Hern (Australia) 67, 71, 64, 68.
272 — Robert Allenby (Australia) 69, 68, 69, 66; Richard Green (Australia) 66, 69, 66, 71.
273 — K.J. Choi (South Korea) 65, 66, 70, 72
274 — Francesco Molinari (Italy) 71, 65, 66, 72; Ian Poulter (Britain) 70, 66, 69, 69; Adam Scott (Australia) 64, 71, 70, 69.
275 — Fred Couples (US) 71, 67, 65, 72; David Diaz (Australia) 69, 72, 64, 70; Gavin Flint (Australia) 72, 64, 66, 73.
276 — Chris Campbell (Australia) 71, 67, 67, 71; Ross Fisher (Britain) 69, 67, 68, 72; Shiv Kapur (India) 68, 71, 67, 70.
277 — Andrew Buckle (Australia) 73, 69, 67, 68; Paul Casey (Britain) 68, 69, 67, 73; Prayad Marksaeng (Thailand) 72, 66, 70, 69.
278 — Steve Allan (Australia) 72, 69, 67, 70; Sung-Man Lee (South Korea) 71, 71, 64, 72; Craig Parry (Australia) 68, 70, 65, 75.
279 — Kim Felton (Australia) 71, 68, 67, 73; Nick Flanagan (Australia) 72, 68, 66, 73; Scott Gardiner (Australia) 70, 66, 74, 69; Soren Kjeldsen (Denmark) 70, 71, 67, 71; Stephen Leaney (Australia) 70, 66, 69, 74; Leigh McKechnie (Australia) 73, 66, 70, 70; Peter O’Malley (Australia) 69, 70, 67, 73; Peter Senior (Australia) 68, 68, 72, 71; Steve Webster (Britain) 71, 68, 68, 72.
280 — Angel Cabrera (Argentina) 73, 68, 71, 68; Tony Carolan (Australia) 66, 69, 75, 70; Ian Garbutt (Britain) 71, 69, 70, 70.
DUO SHARE LEAD
PEBBLE BEACH (California): Mike Weir birdied three of the last eight holes to snatch a share of the lead with Arron Oberholser in the Pebble Beach National Pro-Am third round on Saturday.
Canadian Weir, three strokes clear overnight, was overhauled by Oberholser earlier in the day but his late surge for a three-under-par 69 at Spyglass Hill left him at 17-under 199.
Local favourite Oberholser picked up shots at two of his last three holes for an impressive 66 in strengthening afternoon sea breezes at the Pebble Beach Golf Links.
Leading third round scores:
199 — Arron Oberholser (US) 65, 68, 66; Mike Weir (Canada) 63, 67, 69.
205 — Luke Donald (Britain) 62, 72, 71.
206 — Nick Watney (US) 65, 71, 70; Rory Sabbatini (South Africa) 69, 69, 68; Brian Davis (Britain) 66, 72, 68; Harrison Frazar (US) 67, 72, 67.
207 — Tim Clark (South Africa) 66, 71, 70; Daniel Chopra (Sweden) 71, 67, 69; Mark Wilson (US) 68, 68, 71.
208 — Ryan Palmer (US) 69, 71, 68; Hunter Mahan (US) 68, 73, 67; Phil Mickelson (US) 67, 74, 67; Fredrik Jacobson (Sweden) 67, 67, 74; Jonathan Byrd (US) 69, 65, 74; Lee Janzen (US) 69, 73, 66.
209 — Tom Lehman (US) 72 65 72; John Senden (Australia) 72, 69, 68; Will MacKenzie (US) 70, 69, 70; Bo Van Pelt (US) 67, 71, 71; Craig Barlow (US) 69, 68, 72.
210 — Jose Maria Olazabal (Spain) 71, 67, 72; Pat Perez (US) 69, 71, 70; Jerry Smith (US) 69, 68, 73; Chris DiMarco (US) 68, 69, 73; Joe Ogilvie (US) 70, 71, 69; Jon Mills (Canada) 71, 67, 72; John Cook (US) 67, 70, 73; Paul McGinley (Ireland) 71, 68, 71; Darron Stiles (US) 66, 71, 73; Dean Wilson (US) 68, 70, 72; Alex Aragon (US) 68, 69, 73.—Reuters