After a 28-year absence, Eintracht Braunschweig are back in the Bundesliga and coach Torsten Lieberknecht described their promotion as "a huge dream come true" after it was confirmed with three second division games left.
As one of the Bundesliga's founding clubs, Eintracht, relegated in 1985, booked their Bundesliga ticket on Friday night with a 1-0 win away to Ingolstadt.
"It's a huge dream come true. It is unbelievable, it's an incredible day. And it won't be the last," said Lieberknecht, 39, who took over in 2008 when they were in the third division, with a party planned in Brunswick on Saturday.
They will join Hertha Berlin in Germany's top-flight with the pair battling for the second-division title and a third team could follow them into the Bundesliga.
The side which finishes in third place takes on the team third from bottom in the Bundesliga in an end of season play-off.
Braunschweig president Sebastian Ebel said life in the Bundesliga would be "brutally hard".
"We know we'll be the first candidates for relegation, it's not going to be a walk in the park," he said.