Nathan Chen became the first American to win the men’s gold - or any medal - at the International Skating Union World Figure Skating Championships since 2009 as he went for six quadruple jumps in Milan.
The 18-year-old from Salt Lake City, already the Grand Prix Final champion, emulated the achievement of Evan Lysacek nine years ago at the Mediolanun Forum.
Japan's Olympic silver medallist Shoma Uno moved up from fifth place overnight to earn a second world silver, with Mikhail Kolyada claiming bronze for Russia.
Skating to "Mao’s Last Dancer" and "Sacre du Printemps", Chen reeled off a quad Lutz, a quad flip-double toe, a quad flip, a quad toe and a quad toe-triple toe.
He also landed a triple Axel and a triple flip-single loop-triple Salchow combination.
The only problem came when he stepped out of the sixth quadruple jump, a Salchow.
Chen set a personal best of 219.46 points in the free skating to total 321.40 after leading following the short routines.
It comes after falls dented his chances of success at last month's Pyeongchang 2018 Winter Olympics.
"It's just a dream come true, it's something I have wanted to achieve my whole career and I'm just so glad I was able to do it," Chen said.
"I'm glad I was able to do what I needed to do and I felt the audience really wanted a good performance and they motivated me to do it."
Uno, reportedly handicapped by an ankle injury, scored 179.51 points which added up to 273.77 overall.
"My foot felt better than yesterday, it was hard to bring it in a good condition," he said.
"I did mistakes in the beginning, but I am satisfied that I finished the free skate like this."
Kolyada, the two-time European bronze medallist, had been in second place overnight but slipped to third after earning 172.24, totalling 272.32.
Alexei Bychenko of Israel moved up from seventh to fourth with 258.28.
Kazuki Tomono of Japan was ranked third in the free skating with a clean performance to "West Side Story", moving up from 11th to fifth overall.
The World Figure Skating Championships 2018 concluded with the end of the ice dance competition.
The evening action saw Pyeongchang 2018 Olympic silver medallists Gabriella Papadakis and Guillaume Cizeron of France take their third world ice dance title, setting new highest scores.
The French champions set a new best in the free dance with 123.47 points and overall with 207.20.
Madison Hubbell and Zachary Donohue of the US took silver, their first world medal, and Canada’s Kaitlyn Weaver and Andrew Pojer finished third.
Papadakis and Cizeron, four times European champions, delivered a beautiful dance to Beethoven’s “Moonlight Sonata”, collecting a level four for all elements and 10.00s from all nine judges for performance.
"We’re really happy about what we did today, of course because of the scores but before that because of the feeling we had on the ice,” said Cizeron.
“We had so much fun and felt like we had so much control of what we were doing.
“It was one of the first times we achieved such a level of quality in our programme and the connection was incredible between the two of us and with the public.
“The atmosphere around us felt like a special moment.
“It is a beautiful victory, it’s cool.
“We are very proud of this third gold medal.
“I think this will be one of the moments for us to remember, we beat three world records – in the short, the free and overall.”
Hubbell and Donohue earned a new best of 116.22 points to total 196.64.
The Canadians achieved a personal best of 114.04 points, and 192.35 overall.