Trump, 27, had arrived at the Crucible as the clear title favourite, tipped to match or better his run to the final in 2011.
But the World No2 suffered a painful exit in more ways than one at the hands of McLeod – a journeyman widely known as ‘The Dentist’ on tour.
The 46-year-old McLeod is renowned for his slow play, and on his last visit to the Crucible beaten opponent Ricky Walden likened the match experience as “like a trip to the dentist”.
The name has stuck, but for world No54 McLeod – a player that has never won a major ranking event – this was a stunning success and the win of his life.
McLeod, who won the match 10-8, was a complete outsider when the draw was made. And only next opponent Stephen Maguire had given him any chance against Trump.
Rory McLeod caused one of the biggest upsets in World Snooker Championship history
Trump, believed to have been suffering with a shoulder injury, refused to speak to the media after his defeat and faces a fine,
McLeod, guaranteed £25,000, said: “It is the biggest win of my career, and I don’t know how I held myself together.
“He makes breaks for fun, and is so dangerous. When I was 4-0 down I was actually quite relaxed because there wasn’t much I could do about it.
“But this is just brilliant for me. I think I was in zombie mode from 4-0 up to 4-4 and 5-4 up.
“Shoulder injury? I wasn’t paying any attention to that, just on what I was doing. When I am out there I do close my eyes, try to be still. Sometimes the nightmares come, though!
“But I take my hat off to the top players, they can pull off this kind of thing all the time, this is just one for me.”
Get Quotes on Home Insurance
Judd Trump was the clear title favourite
And his departure will give greater hope to Scots Maguire and also John Higgins, in the same half of the draw.
Over the season Trump’s average shot time (17.83 secs) is almost half that of McLeod (31.43).
But looking like a man having root canal treatment throughout, he was denied any rhythm and even looked in pain towards the end of the match.
The drama was also dragged out, as the pair ran over their allotted finish time with McLeod 9-7 up and had to come back late last night to finish up.
McLeod has never won a major ranking event
McLeod, from Wellingborough in Northamptonshire, won the first professional title of his life only 18 months ago – the Ruhr Open in Germany at the age of 45.
And he has also worked as the coach of the Qatar national team alongside playing on the professional tour.
But it was another desperately disappointing Crucible defeat for Trump, who had enjoyed his best ever season with two titles and three more finals.
Over the entire season Trump’s average shot time (17.83 secs) is almost half that of McLeod (31.43).
Wold Snooker prize money rankings 2017 Thu, April 13, 2017
Express Sport brings you the Wold Snooker prize money rankings
Play slideshow VCG via Getty Images 1 of 10
Ali Carter – £322,575
But looking like a man having root canal treatment throughout, he was denied any rhythm and even looked in pain from his shoulder.
The drama was also dragged out, as the pair ran over their allotted morning finish time with McLeod 9-7 up and had to come back late last night to finish up.
Trump showed some fight by closing the gap to 9-8 and giving McLeod something to think about.
But in the next McLeod, served up with yet another chance, held his nerve and got over the line.