Schalke's last win was a 2-0 win over Borussia Mönchengladbach on January 17, 2020. The German side went into the match knowing anything but a victory would see them level the all-time winless record run in the German top flight, set by amateur side Tasmania Berlin in 1965-66.
But Hoppe, 19, ensured Schalke would not go into the history books as he became the first American to score a hat trick in the Bundesliga and the third to do so in any of Europe's top five leagues.
"I don't know how to feel. I'm excited, I'm happy the team got the win and that I got to contribute to it," said the California native.
Klinsmann: Matthew Hoppe's heroics are a fairy-tale story
Jurgen Klinsmann heaps praise on Matthew Hoppe after the American teenager's heroic hat trick for Schalke.
He follows in the footsteps of Clint Dempsey, who netted a treble in Fulham's 5-2 victory over Newcastle United in 2012, and Christian Pulisic, whose hat trick also came in the Premier League during Chelsea's 4-2 win at Burnley in 2019.
Hoppe is the youngest American to score three goals in a single match in Europe's top five leagues.
This was Hoppe's sixth appearance for Schalke and third start. Having joined from Barcelona's academy in 2019, he spent his first season at Schalke with the club's under-19 side, where he scored five goals in 20 competitive appearances.
This term, Hoppe started in attack for the reserves before he was promoted to the first team in November. Starting in a 4-1 defeat at Borussia Monchengladbach on Nov. 28, he then made two brief appearances as a sub as Schalke's plight worsened towards the end of the year.
He returned to the starting formation in new manager Christian Gross' first match in charge on Jan. 2, but remained without a goal in four games at senior level.
However, against Hoffenheim, Hoppe opened his account for the Royal Blues in style with a lovely chip over goalkeeper Oliver Baumann in the 42nd minute.
On seven points after 15 games, Schalke are now back in the race to avoid relegation.
"It gives some confidence, some momentum," said Hoppe. "We have 19 games left, and hopefully we can keep the wins coming and we can stay high in the first division."