Earlier on Saturday, he was hurriedly taken from a hospital and put on a plane for the United States closing a nearly monthlong diplomatic tussle that had tested U.S.-China relations.
Chen Guangcheng, sitting in a wheelchair and accompanied by his wife and two children, boarded United Airlines Flight 88 for the 12-hour flight to Newark, outside New York City, a few hours after Chinese authorities suddenly told him to pack and prepare to leave.
"Thousands of thoughts are surging to my mind," Chen said at the airport in Beijing. His concerns, he said, included whether authorities would retaliate for his negotiated departure by punishing his relatives left behind. It also is unclear whether the government will allow him to return.
A senior White House official welcomed Chen's departure and praised diplomatic efforts in both Washington and Beijing that defused a standoff over his status. Ben Rhodes of the National Security Council told reporters during the Group of Eight summit the United States is hosting at Camp David, Maryland, "We are pleased that this was able to reach a resolution."
A self-taught legal activist, Chen asked his supporters and others in the activist community for their understanding of his desire to leave the front lines of the rights struggle in China.
"I am requesting a leave of absence, and I hope that they will understand," he said.
The Chens' departure to the United States marks the conclusion of nearly a month of uncertainty and years of mistreatment by local authorities for the activist.
After seven years of prison and house arrest, Chen made a daring escape from his rural village in late April and was given sanctuary inside the U.S. Embassy, triggering a diplomatic standoff over his fate. With Secretary of State Hillary Rodham Clinton in Beijing for annual high-level discussions, officials struck a deal that let Chen walk free, only to see him have second thoughts, forcing new negotiations that led to an agreement to send him to the U.S. to study law -- a goal of his. New York University and another school have offered to host him.
Moments after his departure from Beijing, State Department spokeswoman Victoria Nuland confirmed that Chen was en route to the U.S. and praised the quiet negotiations that freed him.
"We are looking forward to his arrival in the United States later today," Nuland said in a statement. "We also express our appreciation for the manner in which we were able to resolve this matter and to support Mr. Chen's desire to study in the U.S. and pursue his goals."
China's Foreign Ministry said it had no comment. The government's news agency, Xinhua, issued a brief report saying that Chen "has applied for study in the United States via normal channels in line with the law."
Chen's supporters welcomed his departure. "I think this is great progress," said U.S.-based rights activist Bob Fu. "It's a victory for freedom fighters."
The 40-year-old Chen is emblematic of a new breed of activists that the Communist Party finds threatening. Often from rural and working-class families, these "rights defenders," as they are called, are unlike the students and intellectuals from the elite academies and major cities of previous democracy movements and thus could potentially appeal to ordinary Chinese.
Chen gained recognition for crusading for the disabled and for farmers' rights and fighting against forced abortions in his rural community. That angered local officials, who seemed to wage a personal vendetta against him, convicting him in 2006 on what his supporters say were fabricated charges and then holding him for the past 20 months in illegal house arrest.
Even with the backstage negotiations, Chen's departure came hastily. Chen spent the last two and a half weeks in a hospital being given medical treatment for the foot he broke escaping house arrest. Only on Wednesday did Chinese authorities help him complete the paperwork needed for his passport.
Chen said by telephone Saturday that he was informed at the hospital just before noon to pack his bags to leave. Officials did not give him and his family passports or inform them of their flight details until after they got to the airport.
Seeming ambivalent, Chen said that he was "not happy" about leaving and that he had a lot on his mind, including worries about retaliation against his extended family back home. His nephew, Chen Kegui, is accused of attempted murder after he allegedly used a kitchen knife to attack officials who stormed his house after discovering Chen Guangcheng was missing.
"I hope that the government will fulfill the promises it made to me, all of its promises," Chen said. Such promises included launching an investigation into abuses against him and his family in Shandong province, he said before the phone call was cut off.
Chen's expected attendance at New York University comes from his association with Jerome Cohen, a law professor at the university who advised Chen while he was in the U.S. Embassy. The two met when the activist went to the United States on a State Department program in 2003, and Cohen has been staunch advocate for him ever since.
Much as Chen has said he wants return to China, it remains uncertain whether the Chinese government would bar him, as they have done with many exiled activists.
"Chen's departure for the U.S. does not and should not in any way mark a 'mission accomplished' moment for the U.S. government," said Phelim Kine, a senior Asia researcher at Human Rights Watch. "The harder, longer term part is ensuring his right under international law to return to China when he sees fit."
Wu'er Kaixi, an exiled dissident who is on China's list of most wanted student leaders for the 1989 Tiananmen Square demonstrations, made a third unsuccessful attempt Saturday to turn himself in at a Chinese Embassy, this time in Washington, D.C.
However, Chen's friends and supporters cheered Chen's departure. Teng Biao, who had urged Chen after he left the U.S. Embassy to leave China for his personal safety, welcomed the family's departure.
"I feel happy that he and his family can have a normal, free life in the United States with their safety ensured," Teng said.
Nanjing activist blogger He Peirong, who picked Chen up outside his rural village after his escape and spirited him to Beijing, said, "I hope that this will be a good beginning."
Associated Press videojournalist Annie Ho and reporter Charles Hutzler contributed to this report.