Aides had readied a microphone, and the pope appeared to be trying to utter a few words from his studio window. After making a few sounds, he eventually just made signs of the cross and the microphone was taken away.
John Paul coughed briefly when he first appeared, but remained at the window for 12 minutes and looked stronger than he has in recent appearances.
Cardinal Angelo Sodano, who presided over Easter Mass in St. Peter's Square, read the pope's message as the pontiff followed the text from his studio.
Many in the crowd cried, others applauded when the pope appeared.
A physician from Nice, France, Milou Drici, said that "as a doctor, I felt for him. It is an ordeal for him and you could see his frustration. You have to admire his strength and fortitude. The faith of the people, as you saw today, helps him overcome his difficulties."
For the first time since his papacy began in 1978, Easter Sunday Mass at the Vatican began without the pope as he continues his convalescence following two recent hospitalizations for breathing crises.
With this latest absence, John Paul missed participating in all major Holy Week events, a strong indication of his weakened condition.
The last time the pope spoke publicly was March 13, shortly before he was discharged from the hospital.
On Feb. 24, surgeons inserted a tube in John Paul's throat to help him breathe, and since then, the pontiff has uttered only a few words in public.
In his Easter message read by Sodano, John Paul said people were hungering for "truth, freedom, justice and peace."
John Paul also asked God to "give also to us the strength to show generous solidarity toward the multitudes who are even today suffering and dying from poverty and hunger, decimated by fatal epidemics or devastated by immense natural disasters."
A prayer was said during the Mass asking "life and new energies" for the ailing pontiff and the entire Catholic Church.
TV hookups broadcast the service to 74 countries.
Sunday morning began chilly, with a light drizzle. Later the sun timidly broke through the clouds.
"It would have been better with the pope," said Sheri Zimpelman, who was in the crowd at the Sunday service with her husband, a U.S. serviceman stationed in Aviano, northern Italy.
Her husband, Thomas Zimpelman, said: "If he's sick, he should do what's best for him. His presence is enough."
John Paul also skipped the Easter vigil Mass in St. Peter's Basilica on Saturday night, to give him more time to rest up for Sunday's blessing. German Cardinal Joseph Ratzinger, a close papal aide, celebrated the service, and read a papal message in which John Paul assured the crowd that he was watching the Mass on television in his Vatican apartment.
On Friday night, John Paul appeared, via a video hookup, to faithful at the Way of the Cross procession at the Colosseum. John Paul was seen, always with the camera at his back, as he sat in his private chapel and watched the procession on television.
The pontiff traditionally has used the Easter Sunday message to reflect on war, poverty and terrorism. He also developed a tradition of delivering holiday greetings in dozens of languages.
"It pains him to be on the sidelines," the Vatican newspaper L'Osservatore Romano wrote Saturday.