Police said a volunteer search and rescue team found 25-year-old Robert Galdamez wet and cold, just before 12.30am, near the summit of Ben Lomond.
The tourist said he cried with relief when he was found.
"I'm very grateful, it was the most amazing feeling," he said. "I really thought I was going to die to be honest.
He was recovering in hospital but expected to be discharged later today.
Mr Galdamez described how cold and scared he felt throughout his ordeal.
"I was literally just trying to keep warm, pretty much, especially when it started snowing," he said. "I got really scared after that, so I literally just huddled into a circle under my jacket and just tried to keep warm.
"When it started snowing that's when I started getting worried," he said. "It wasn't a good feeling."
He credited his puffer jacket for keeping him alive.
"To be honest if I didn't have that jacket, then honestly I don't think I'd be here. Even with that jacket on it was very very cold, at that point I got very worried for my family, if something happened to me."
About 20 search and rescue staff, specialist dogs and a helicopter with night vision equipment combed the mountain overnight, locating him at 12.20am today, near the summit.
Senior Sergeant Paula Enoka, of Queenstown, said the search and rescue team would hold a debrief this afternoon and an officer would speak to Mr Galdamez to understand what had happened.
"As far as I understand it ... he was found in an area that we'd been over a number of times."
Yesterday his partner Tim Heritage said Galdamez was no stranger to tramping, but he was ''fearing the worst''.
Mr Galdamez and a friend had arrived in Queenstown on Monday and were scheduled to return to Australia on Saturday.
Mr Heritage understood the pair had initially intended to walk Ben Lomond, above the Skyline complex, together.
''Apparently his friend only walked 30 minutes with him and didn't want to go any further, or couldn't or something, so she turned back and he went off.
''While he was walking up the mountain I was at work and I was kind of ... talking to him while working.''
Mr Heritage said Mr Galdamez had sent him some photos of ''up the top'' of Ben Lomond as well as videos of him walking up.
''It looked pretty windy,'' Mr Heritage said.
''He did say he was getting scared and I kept asking him 'Are you all right?' ... and he didn't respond to my messages.''
After an hour without a response from Mr Galdamez, Mr Heritage made contact with the tourist's friend, who said she had tried to video-chat with the missing man, but either something went wrong with the internet, or the battery on his iPad - from which he had been messaging - ran out.
Mr Galdamez, who had been planning to trek to the Everest base camp in December, had a history of epilepsy, Mr Heritage said.
Mr Galdamez was of El Salvadorean and Laotian descent, but born in Australia.
- additional reporting New Zealand Herald/David Williams
