Juan Arango gave Gladbach the lead after eight minutes with a thumping long-range effort while Luuk de Jong made it two in the 24th minute.
Gladbach, who had not won since the first weekend of the season, move onto nine points while Frankfurt stay in second on 16 - five points behind Bayern Munich.
Gladbach went ahead after eight minutes courtesy of a wonderful strike by Arango.
Olivier Occean lost the ball in his own half before the Venezuelan unleashed a powerful effort from 30 yards that flew in off the underside of the crossbar.
Frankfurt missed a fine chance 10 minutes later as Occean chested the ball down ahead of Gladbach goalkeeper Marc-Andre ter Stegen, turned towards the empty goal but missed the target from a tight angle.
The hosts were more effective and doubled the lead after 24 minutes as Havard Nordtveit played a long ball over the defence to De Jong, who raced past Carlos Zambrano before unleashing a powerful strike to the right side of Kevin Trapp.
Gladbach found the back of the net again in the 37th minute but Lukas Rupp was ruled offside, while Frankfurt were close to getting on the scoresheet in the 56th minute when Stefan Aigner struck the crossbar.
Occean's tough day continued as he sent a bicycle kick just inches over the framework with 14 minutes remaining.