A stunning extra-time goal from Mario Goetze was enough for Germany to win the World Cup for a fourth time.
With penalties looming, Goetze, a second-half substitute for Miroslav Klose, expertly controlled Andre Schuerrle's cross with his chest before volleying past Sergio Romero.
Twenty-four years after their last World Cup triumph, which was also achieved against Argentina, Germany could celebrate again - coach Joachim Loew realising a dream that began eight years ago when he first took charge of his national team.
It is the first time a team from Europe has won the World Cup on American soil.
The goal, deep into extra-time, followed an opening 90 minutes of two very different halves.
The first half was an open affair in which both teams will have felt they should have scored.
The magnificent Maracana was a sea of blue and white, with Argentina fans comfortably outnumbering their European counterparts. After a tense opening 20 minutes, they watched on agog as Gonzalo Higuain missed a wonderful opportunity to open the scoring.
The normally unflappable Toni Kroos looped a headed back-pass in the direction of goalkeeper Manuel Neuer, but all he did was send Higuain through on goal. The Argentina striker, perhaps with too much time to think, opted to blast the ball, but only succeeded in dragging the shot wide.
Minutes later, Higuain did have the ball in the net when he calmly slotted home Ezequiel Lavezzi's inch-perfect pass, but was ruled offside.
Lionel Messi was next to go close when he burst free down the right-hand side. The Barcelona forward poked an effort forwards, but Neuer managed to get a hand on it and Jerome Boateng cleared before Messi could follow up.
Germany, though, ended the half on a higher note. Chelsea's Schuerrle, only just on as a substitute for Christoph Kramer - himself a last-minute replacement for Sami Khedira who hurt himself in the pre-match warm-up - produced a brilliant save from Romero with a side-footed effort from the edge of the area.
Then, with the clock ticking into injury time, Benedikt Hoewedes rose highest to meet Kroos' floated corner only to crash the ball against the post.
Just 30 seconds after the restart, Messi was again disappointed when he dragged a shot wide, but the it was a far tenser affair after the break.
Klose, the World Cup's all-time leading scorer after notching his 17th in the 7-1 semi-final drubbing of Brazil, had a good chance to open the deadlock but his header from Philipp Lahm's cross was into the ground and easy for Romero.
Minutes from the end, Kroos' control again let him down when he was set up by some good work from Lahm and Oezil down the right-hand side.
The match burst back into life after the 90 had ended, Romero saving well from Schuerrle before, at the other end, Palacio lifted the ball over Neuer, only to see it creep wide.
In the second half of extra-time Aguero appeared to be fortunate to escape a red card as he seemed to swing a punch towards Bastian Schweinsteiger that left the Germany midfielder bleeding from below his eye.
But it was to be Germany who delivered the knockout blow, Bayern Munich playmaker Goetze finishing with aplomb with just seven minutes remaining.