After falling behind to efforts from Clint Dempsey and Landon Donovan, the South Americans looked out of ideas when they left the field at half-time.
But Sevilla striker Luis Fabiano pulled one back immediately after the restart, before drawing his side level with 16 minutes still to play.
Captain Lucio then had the final say when he powered home from an Elano corner to break American hearts and claim Brazil's third title.
Before kick-off FIFA honoured Marc-Vivien Foe, the Cameroon midfielder, who collapsed with a heart problem during the 2003 finals in France, with his son Marc Scott delivering a message in memory of his late father.
On the field, Dempsey had an early 20-yard shot fired wide for the Americans, while Kaka's glanced header from a Robinho corner and Andre Santos' ambitious long-range drive followed the same path.
But the Brazilians were stunned in the 10th minute when Jonathan Spector delivered a fine cross from the right that was turned home by Dempsey from the centre of the penalty area - the Fulham forward's first-time touch leaving both Gilberto Silva and Lucio as onlookers as the ball was guided past Julio Cesar.
The South Americans tried to hit back with Kaka turning neatly in midfield and laying a beautiful pass on for Robinho, whose curled shot from the left was goal-bound until Tim Howard intervened to turn it wide for a corner.
Bob Bradley's men again had their goalkeeper to thank seconds later after he blocked shots from Felipe Melo and Maicon, although both were struck straight at him.
And they were dealt another massive blow in the 27th following with a sweeping counter-attack that was started and finished by Donovan.
The Los Angeles Galaxy frontman picked the ball up on the halfway line and then spread it wide to Charlie Davies on the left, before collecting the return pass just outside the box, easing his way past Ramires and blasting a fine left-footed finish beyond Julio Cesar.
The shell-shocked defending champions again tried to rebuild, with Andre Santos shooting straight at Howard, followed by Luis Fabiano heading over a corner.
The Everton goalkeeper again denied Robinho five minutes before the break when he tipped over from the Manchester City striker as Brazil went into the break frustrated and out of ideas.
But Dunga's half-time talk helped his players up the ante as they struck back in the 46th minute with Maicon finding Luis Fabiano just inside the box, and the Sevilla striker turned nicely, before firing low beyond Howard.
The American stopper continued to be kept busy with skipper Lucio forcing him to block from a close-range header.
Kaka's header then looked to have crossed the line - the Real Madrid playmaker nodded the ball goalward, with Howard punching it away off the crossbar, but replays showed it went in.
Donovan and Dempsey finally helped their side hit the target in the second half with their first attack coming just after the hour mark, but on both occasions Julio Cesar was there to punch the ball away.
But the pressure proved too much at the other end and, after seeing Howard steal the ball from his feet, Luis Fabiano was on hand to convert a Kaka cross which skimmed across the face of the goal from the left - Robinho's initial shot hitting the crossbar and falling into the path of his strike partner.
The equaliser came after 74 minutes and, shortly after Robinho powered agonisingly over from 20-yards out, Lucio met Elano's corner with thundering header that flew into Howard's top right-hand corner to complete a thrilling comeback.