Twenty-five years ago today, he appeared on the world stage as the first non-Italian pope in more than four centuries. Soon, the robust man with a charismatic presence and thirst for globe-trotting became a media star.
But even in an age of celebrity, it takes more than media appeal to capture the world's attention - and hold it for a quarter-century.
John Paul II has transformed the papacy, taking the church to the people. He's left an indelible mark on the world, playing a key role in the collapse of communism and becoming a strong moral voice for Catholics and non-Catholics alike on the primacy of freedom and spiritual values.
"He has established the papacy as an almost universally recognized center of public moral deliberation about the kind of world in which we live," says the Rev. Richard John Neuhaus, editor of First Things.
And he's placed his stamp firmly on the Roman Catholic Church. Hewing to a staunch traditional Catholicism, the Polish-born leader both renewed allegiances and stirred controversy among the faithful.
"Pope John Paul II presided over an acute polarization of the church between its conservative and liberal wings," says the Rev. John Langan, of the Kennedy Institute of Ethics at Georgetown University in Washington.
As the pope undertakes a grueling week of events to celebrate his silver anniversary, beatify Mother Teresa, and induct 31 new cardinals, his health is at the forefront, with persistent questions about how the church will be governed should he be incapacitated. The pope alone is authorized to decide that.
John Paul II has indicated he plans to stay on until God tells him to do otherwise. Yet even as some say this pontificate has gone on too long, it's clear he still holds the admiration of millions.
And many would agree with his biographer, George Weigel, who calls this "the most consequential pontificate since the 16th-century Reformation."
Most visibly, the familiar white-clad figure has redefined the papacy as global pastor and evangelist, traveling to some 130 countries, kneeling to kiss the soil, and embracing those in dire straits.
Yet his outreach has been more than symbolic. His voice has been the clearest not only in support of the poor, but against utilitarian worldviews that fail to put human beings at the center of concern. In his religious writings, he strongly supports democracy and free enterprise, but also highlights inequities of capitalism and globalization.
A driving aim of his papacy has been to detail a Christian alternative to the humanistic philosophies and theories of the late 20th century. His voice was crucial in prompting the Jubilee 2000 campaign that won significant debt relief for the world's poorest countries.
The pope's greatest legacy, most people agree, is his role in spurring Communism's collapse, a role acknowledged by Mikhail Gorbachev. His trips to Poland helped give rise to the independent trade union Solidarity, and he intervened with Soviet and Polish leaders when crackdowns seemed imminent. Solidarity's success lit the flame of nonviolent revolution in Eastern Europe.
In a period of religious conflict, John Paul II has also taken bold initiatives to strengthen interreligious ties, apologizing for past church actions toward Muslims and Jews. Rabbi James Rudin of the American Jewish Committee credits him with doing "more to strengthen Catholic-Jewish relations than any other pope in history."
He is the first pope to visit a mosque, and his visible, persistent efforts to head off the war in Iraq, though unsuccessful, are seen as key to convincing Muslim leaders that it was not a Christian campaign against Islam.
His greatest disappointment lies in his failure to end the schism with Eastern Orthodoxy.
Not all the pope's efforts have won widespread plaudits. The church has been criticized, for example, for its successful intervention at the 1994 UN population conference to keep abortion from being considered as a family-planning method, and for its continuing rejection of contraceptive measures that could protect people from AIDS and reduce demand for abortion.
Within the Catholic Church itself, the impact of this fourth-longest pontificate in history is also mixed. The pope's personal piety, compassionate outreach, and global stature have won him tremendous affection. "This is a man who truly lives what he believes," says Marion Gaworecki, of Lynwood, N. Y. "He's renewed my faith and that of other Catholics."
He has always had a special rapport with youths, and some see evidence on Catholic campuses of growing identification with his teachings.
Sandra Yocum Mize, who teaches religion at the University of Dayton, in Ohio, says many young people are being "attracted to the challenges the pope issues - to chastity, to bring Christ into the world, to stand against abortion, to stand for the poor and against other kinds of social injustice."
Yet the church also faces serious problems, Catholics say, including the conservative-liberal split and a legacy of increasingly centralized power. The failure of church leaders, including the pope, to act swiftly to address the crisis of clergy sexual abuse and embrace the victims weakened the moral authority of the church in the eyes of many, particularly in the US. It led some Catholics to reduce or withhold contributions or even to stop attending altogether.
The pope is criticized, too, for prohibiting discussion about married priests and women's ordination, both of which have strong support from Catholics in many countries. Many Catholics say this makes no sense because of the serious lack of priests worldwide, which threatens the essence of Catholic worship, the Eucharist.
During John Paul's papacy, the number of Catholics has grown by 40 percent, from 750 million to more than 1 billion, according to church statistics. The total number of diocesan priests has gone up by only 8,000, and those in religious orders have declined.
Most serious for the future of the church, observers say, may be the fact that millions of Catholics are no longer paying attention to basic teachings, such as those on contraception, divorce, and abortion.