Hend carded a closing 68 at Black Mountain Golf Club to finish 18-under-par, one shot ahead of world no.798 Swangarunporn, who had surged through the field with a course-record 63.
Swangarunporn began the day six shots off the lead but wiped out that deficit with six birdies and an eagle in the first 14 holes, before another birdie on the 18th set an imposing clubhouse target.
Hend's two-shot overnight lead had been wiped out in the space of two holes after Belgium's Thomas Pieters birdied the first and holed out from a bunker for an eagle on the second, but Hend responded with birdies on the second and fourth.
The 43-year-old, who also led after 54 holes in 2015 before finishing second, birdied the 10th before a bogey on the 12th dropped him back into a share of the lead with Swangarunporn, who was seven groups ahead.
A birdie on the 14th took Hend back into a tie for the lead and after driving the green on the 366-yard par four 17th and safely two-putting for birdie, he could afford to three-putt the 18th for par and secure a second European Tour title.
"Last week I did not really have any patience and this week I just hung in there," said Hend, who only arrived in Thailand at 1am on Wednesday after making the long journey from Miami, where he shot 22-over-par to finish 63rd in the 66-man field in the WGC-Cadillac Championship.
"If I did make a mistake I didn't get upset about it and just rolled with the punches.
"For Piya to shoot 9-under was an amazing score out there, he has obviously played extremely well, but I knew I just had to cruise along and do what I do best and that's get in position and make birdies.
"Last year I pushed too hard and it hurt me on 17 (where he made bogey) and I ended up losing by a shot. This year I just sat back and let the golf course come to me and I'm lucky enough to be here with the trophy. It's bloody awesome."
The victory is set to lift Hend to a career-high inside the world's top 80 and he has his sights set on climbing further up the rankings to qualify for the game's biggest events.
"It would be nice to win again [in 2016] and to try to qualify for the Open and US Open and work my way towards all the big events the elite golfers are playing and try to battle it out with some guys in the top 50 in the world," Hend added.
Swangarunporn was playing only the second European Tour event of his career after finishing 50th here last year and does not even have a profile picture on the website.
"Today was one of the best rounds I have ever played. Everything about the game was good and it all came together for me," the 32-year-old said. "It was very exciting but I tried to stay calm and to keep making birdies.
"It is a big day for my career and I hope to play more big tournaments like this one in the future because this week has given me a lot of confidence."
Pieters was unable to maintain his blistering start but claimed third place on 15-under after a closing 68, a result good enough to confirm his place in the WGC-Match Play the week after next. First-round leader Peter Uihlein was another shot back in fourth.