A two-time All-Star, Uggla hit .287 with 33 homers and 105 RBIs last season and had been discussing a possible contract extension with Florida. He made $7.8 million this year, is eligible for salary arbitration and can become a free agent after the 2011 World Series.
"We're not satisfied he's here for one year," Braves general manager Frank Wren said. "He's a kind of guy we'd like to make long-term."
The trade reunites Uggla with former Marlins manager Fredi Gonzalez, hired by the Braves to succeed Bobby Cox following the longtime Atlanta manager's retirement.
Florida is close to replacing some of the lost power with free-agent catcher John Buck, who is nearing agreement on an $18 million, three-year contract.
Martin Prado split time between second and third this year for the Braves, and the trade could be a sign Atlanta is unsure whether third baseman Chipper Jones can return next year from surgery to repair a torn ligament in his left knee. Jones turns 39 in April.
Wren said Uggla will play second.
"Martin plays left field as his primary position in winter ball, though he's not playing this year," Wren said. "So we have some flexibility depending on how Chipper responds."
Marlins president of baseball operations Larry Beinfest said the trade followed the failed contract talks. Uggla was taken from Arizona in the 2005 winter meeting draft when he was left unprotected.
"The deal just didn't work out. We just made the decision," Beinfest said. "Dan is a great guy. He understands. He's a great story in a lot of ways from where he came from five years ago to where he is today."
Terry Bross, Uggla's agent, said the player was in Mexico on a Nike tour and not available to discuss the trade.
"He loved Florida and wanted to remain a Marlin," Bross said. "I'm sure he's saddened by not being a Marlin anymore. But he'll be exited to be a Brave."
Florida offered Uggla a $24 million, three-year extension during the summer, a person familiar with the talks said, speaking on condition of anonymity because those details were not announced. The person said Uggla countered with a $71 million, five-year proposal.
In recent weeks, the Marlins increased their offer to $48 million over four years, and Uggla remained with his initial proposal.
Bross declined comment on those figures. He said he would be willing to discuss a multiyear deal with the Braves but called it a step-by-step process and said he will wait to hear from Atlanta.
Infante was a first-time All-Star who hit a career-high .321 with eight homers and 47 RBIs. Dunn was 2-0 with a 1.89 ERA in 25 games in his rookie season.
"There could be a little downturn in the power," Beinfest said, "but it's a different look now for the Marlins to get the high average, high on-base guy and then hopefully the guys in the middle, Hanley (Ramirez) and (Mike) Stanton can drive those guys in."
While the teams had been in discussions for awhile, it came together when the GMs gathered for their annual get-together.
"I think we exchanged some names 10 days ago or 12 days ago," Wren said. "As we got into our meetings (Tuesday), I think it was just by happenstance, we happened to be sitting beside each other. We didn't have assigned seats as we normally do. We started talking and it progressed by late in the morning we were exchanging names and were in basic agreement what the deal would be. It was just going ahead and getting some additional information."
Buck's negotiations were disclosed by a second person, who spoke on condition of anonymity because the deal was not yet final. The person said the sides were working to wrap it up.
Buck was a first-time All-Star this year, when he hit .281 with 20 homers and 66 RBIs for the Toronto Blue Jays.