Shane Bertsch shot a 3-under 67 on Sunday to take third place at 11-under-par 269. Mike Sullivan also carded a 3-under 67 in the final round and came in fourth at minus-10.
The third round was completed Sunday morning after darkness halted play on Saturday. A Thursday weather delay pushed the tournament back, but a six-hour rain stoppage on Saturday allowed only 18 players to finish their third rounds before Sunday.
Langham trailed Cotner when play was stopped after the 11th hole of the third round, but Langham ended up with the third-round lead.
Langham mixed four birdies and a bogey in a six-hole span on his front nine, but Cotner matched his 3-under score to stay one behind.
Cotner fell off the pace with a bogey at No. 10 and both players tallied two birdies between holes 11-14. Langham's birdie at 14 was huge for him as it erased memories of collapse in 2003.
Last year, he squandered the lead on the back nine and PGA Tour player Zach Johnson took home the trophy. It was at 14 where Langham drove into the woods and ended his chances but on this Sunday, he hit a 7-iron to 12 feet for birdie.
Cotner bogeyed the 16th to fall three back. Langham dropped a stroke at the 17th but hung on at 18 for his first victory of the 2004 campaign.
'We didn't hear a lot of roars around the golf course and Keoke and I were making birdies so I didn't figure there was anybody real close to us,' said Langham, who moved to fourth on the tour's money list with his $85,500 first-place check. 'We did a lot of seesawing.'
Langham, who played several seasons on the PGA Tour, picked up his second win on the Nationwide Tour, albeit several years apart. His last win on tour was the 1993 Permian Basin Open and with the win on Sunday, he set a new tour record for longest span between victories, 10 years, eight months and 17 days.
'It's been a long time since I won,' he said. 'I knew it wasn't going to be easy and it wasn't. Last year I was in a bit of a funk and never had a good outlook on golf but I made the decision to rededicate myself. It's a good feeling. This is huge.'
Cotner finished with a 3-under 67 on Sunday.
Jeff Hart (69) and Ahmad Bateman (68) shared fifth at 8-under-par 272, followed by Andrew Morse, who took seventh place at minus-7, after a final-round 67.
Paul Gow (69), Justin Bolli (71) and James Driscoll (71) tied for eighth place at 6-under-par 274.