House Speaker Nancy Pelosi said in a statement, “Congress and the Country are overjoyed to learn that, thanks to the committed and focused leadership of President Biden, Brittney Griner is finally free. Today, our hearts are with her dear wife, Cherelle, and the entire Griner family as their beloved Brittney is safely on her way back to America and will be home for the holidays."

“For nearly ten long months, Brittney Griner suffered unthinkable trauma as she was wrongfully imprisoned by the Russian government," Pelosi said. "Putin’s cruelty against Brittney – and his monstrous actions against Ukraine – are staggering reminders of his brazen contempt for human rights, human dignity and the rule of law."

The road to Griner’s release involved "painstaking and intense negotiations," President Biden said as he thanked many across his administration who "worked tirelessly to secure her release."

"She's relieved to finally be heading home and the fact remains that she's lost months of her life, experienced a needless trauma," he said. "She deserves space, privacy and time with her loved ones to recover and heal from her time being wrongfully detained."

Biden said Griner landed in the United Arab Emirates and that the country helped facilitate the transfer.

Paul Whelan was not part of this exchange, the president said, adding, "This was not a choice of which American to bring home."

"Sadly, for totally illegitimate reasons, Russia is treating Paul's case differently than Brittney's. And while we have not yet succeeded in securing Paul's release, we are not giving up. We will never give up," Biden said. "We remain in close touch with Paul's family -- the Whelan family -- and my thoughts and prayers are with them today.

"They have to have such mixed emotions today," he continued. "And we’ll keep negotiating in good faith for Paul Whelan. I guarantee that. I say that to the family. And I guarantee you. I urge Russia to do the same to ensure that Paul's health and humane treat are maintained until we can bring him home. I don't want American to be detained one extra day if we can bring that person home."

-ABC News' Justin Gomez

Secretary of State Antony Blinken said he’s grateful to everyone “who worked tirelessly” to bring Brittney Griner home, but lamented that Paul Whelan and his family “continue to suffer needlessly.”

“Despite our ceaseless efforts, the Russian Government has not yet been willing to bring a long overdue end to his wrongful detention. I wholeheartedly wish we could have brought Paul home today on the same plane with Brittney,” he said in a statement. “We will not relent in our efforts to bring Paul and all other U.S. nationals held hostage or wrongfully detained abroad home to their loved ones.”

-ABC News’ Shannon Crawford

President Joe Biden confirmed that WNBA star Brittney Griner is on her way back to the U.S. and will be back within 24 hours.

The president said she's in "good spirits."

"She's safe. She's on a plane. She's on her way home,” Biden said.

“After months of being unjustly detained in Russia held under intolerable circumstances, Brittany will soon be back in the arms of her loved ones and -- and she should have been there all along," he said.

A senior U.S. official told ABC News that Biden signed off on the prisoner swap last week.

-ABC News' Justin Fishel and Justin Gomez