The plane landed at Fort Belvoir, Virginia. Siamak Namazi was the first of the freed Americans off the aircraft.
"The nightmare is finally over," the Associated Press reported his brother Babak as saying at the airport.
Morad Tahbaz, Emad Sharghi and two other American citizens who have not yet been named were also released.
Mr Namazi and the other former detainees also posed for a group photograph with their loved ones and shouted: "Freedom".
The five Americans left Iran on Monday for Doha, where they were greeted at the airport by US ambassador to Qatar Timmy Davis.
US President Joe Biden welcomed the return of the Americans in a statement, while also announcing new sanctions against Tehran on Monday.
"As we celebrate the return of these Americans, we also remember those who did not return," he said, mentioning former FBI agent Robert Levinson, who Washington assumes is dead.
Iranian President Ebrahim Raisi, who is in New York for the UN General Assembly, said the prisoner swap was a "humanitarian action" and opened the door for further co-operation.
"It can certainly be a step based upon which in the future other humanitarian actions can be taken," he said.
The White House maintains that the $6 billion in frozen funds is being transferred from South Korean accounts to restricted accounts in Qatar. National Security Council spokesman John Kirby said Iran could request withdrawals for humanitarian purposes, which will be monitored by the US.