Braunschweig return to Bundesliga after 28 years
Braunschweig, Bundesliga champions in 1967 and relegated in 1985, join Hertha Berlin in winning automatic promotion.
"It is an amazing day," coach Torsten Lieberknecht told reporters as celebrations kicked off with a beer shower on the pitch. "The tears we shed will not be the last ones."
Braunschweig have 65 points, one fewer than Hertha. Third-placed Kaiserslautern, on 52, have four games to play.
Damir Vrancic scored the only goal with a last-gasp free-kick.