The private jet carrying Sean Goldman, and his U.S. father, David Goldman, landed at Orlando International Airport after the nine-hour flight from Rio de Janeiro.
The plane was chartered by the U.S. television show Dateline NBC and other media were kept away. An NBC reporter on the plane said the boy played puzzles and slept during the flight.
David Goldman's home is in New Jersey, but the father was seeking time in private with his son in Florida after the reunion. Brazilian media quoted a Brazilian lawyer for the father as saying he would be taking his son to Disney World in Orlando.
The legal battle over the boy led to testy exchanges between top government officials of the two countries and briefly threatened to interrupt billions of dollars of U.S. trade benefits to Brazil.
Earlier on Thursday, David Goldman and his son were reunited at the U.S. consulate in Rio de Janeiro.
There were lots of smiles, hugs. They talked about basketball and the snowfall in New Jersey just recently, how much fun it is to play in the snow, said Chris Smith, a U.S. congressman from New Jersey who flew to Brazil to help Goldman.
That was a wonderful experience. There was nothing to suggest distance, Smith told a teleconference.
The boy was treated to a hamburger and a Coke at the consulate, he added.
David Goldman had fought since 2004 to bring his son home to New Jersey after his then-wife and Sean's mother, Bruna Bianchi, brought the U.S.-born boy to her native Brazil and then divorced Goldman.
Bianchi died last year while giving birth to a daughter but her second husband and her family sought to keep custody of Sean.
The handover was dramatic. The startled-looking boy, wearing a T-shirt with Brazil's green and yellow colors, clutched his stepfather as the two pushed their way through a mass of reporters outside the consulate where his father was waiting.
At times, Sean covered his face from cameras. His teary-eyed Brazilian grandmother, who has campaigned publicly for the right to raise the boy herself and appealed to Brazilian President Luiz Inacio Lula da Silva to intervene, entered separately without comment.
Goldman, who has seen Sean only in brief visits to Brazil since 2004, cried out, They're hurting my son! upon seeing the scrum, Smith said.
The U.S. father later told NBC he would allow the Brazilian grandmother to visit Sean in the United States. It will take time, but I won't deny her, or him, to know each other, he said.
U.S. Secretary of State Hillary Clinton and a New Jersey senator had protested the long legal battle by delaying a trade measure to extend billions of dollars of duty-free benefits on some Brazilian exports.
In Washington, Clinton issued a statement saying she was thrilled that the boy was reunited with his father and thanked everyone who brought the issue to a successful conclusion.
The U.S. government had regarded the case as an abduction.
On Tuesday, the chief justice of Brazil's Supreme Court put an end to long-running judicial ping-pong that left the case bouncing from one court to another, ruling that Sean must be returned to Goldman.
Bianchi's family and her second husband fought to keep Sean in Brazil, saying he was settled in the country and did not want to go back to the United States.