Having led 6-3 on Monday, world No.42 Noppon finished off the 2005 world champion 10-4 for what he decribed as the biggest win of his life.
The 28-year-old from Samut Prakan became the only third Thai to win at least a match at the Crucible after James Wattana and Dechawat Poomjaeng.
But it is still a long way for Noppon to match Wattana’s semi-final spot at the Crucible in 1993.
In the second round, Noppon will meet Mark Selby or Jordan Brown.
“This is the biggest win of my life. It’s my dream,” said Noppon, widely known in his native country as Moo Paknam.
“I am surprised. I couldn’t sleep last night [Monday] because I was 6-3 up. I went to sleep at 1am and woke up at 5am. I still can’t believe I beat him. I just tried to concentrate on every shot, just focusing on the table.
“I thought about the people in Thailand watching me. I hope they are happy and proud of me. I would like to play Mark Selby next, I will try my best.”
During the COVID-19 lockdown, Noppon sold kun chiang (Chinese pork sausage), specially made by a factory near his house in Samut Prakan, to make ends meet.
“Don’t be ashamed to work for a living. Don’t look down on small money,” Noppon said at the time.
Reaching the last 16 at the Crucible, he is guaranteed £30,000 (B1.2 million) in prize money.
It may have been a best-of-19 match but the turning point came as early as the second frame on Monday when Murphy, leading 1-0, missed a straightforward red on a break of 67 and his opponent punished him with a fine clearance.
That set the tone for the match as former world U21 champion Noppon pounced on Murphy’s errors.
The Thai led 6-3 overnight and took the first two frames yesterday with breaks of 53 and 63.
He had a chance in the next as well but missed a tricky red to centre on 52 and Murphy made a 46 clearance for 8-4.
But that did not spark a fightback, as Noppon recovered to take frame 13 with a run of 60 to lead 9-4 at the interval, and he soon wrapped up victory with a run of 76 in frame 14.
Defeat extends Murphy’s poor run of results at the Crucible in recent years as he has now lost in the opening round in three of his last five appearances, and in the second round on the other two occasions.
Overall it has been a fine season for the world No.10 - he has won two ranking events in a single campaign for the first time in his career - but the enforced break caused by the COVID-19 pandemic ended his momentum and he lacked sharpness throughout this contest.
Murphy said: “That performance did come as a surprise to me as much as anyone, I didn’t see it coming. My preparation has been very good, I have put a lot of time in on the practice table. My form has been good this season with two titles and other finals, so this was a shock to me. But we are all human.
“I was very much below par across the whole match. Probably the worst two days of my snooker year came together at the worst possible time.
“But that aside, Noppon played very well, I can only heap praise on him. I made mistakes but that was because he put pressure on me and had me under it right from the word go.”
Brandon Parker, Murphy’s former manager and close friend, passed away last month but he refused to use that as an excuse for defeat.
“I came here wanting to honour Brandon’s memory as well as I could,” added the 37-year-old.
“You dream of winning the title and dedicating it to him. But I would never dishonour him by saying that has caused me a problem. This is just a snooker tournament.
“I tried my absolute best, and I lost.”