Rigali, 68, is regarded as an orthodox prelate committed to the teaching authority of Rome and his friend Pope John Paul II.
His installation occurs at a challenging moment in the life of the church, as some American Catholics demand greater accountability of the hierarchy in light of the recent sex-abuse scandals, and John Paul's poor health prompts speculations about his successor.
The Pope sent greetings to "the Archdiocese of Brotherly Love" via his emissary to the United States, Archbishop Gabriel Montalvo.
The archdiocese's auxiliary bishops gave ceremonial approval to the papal document announcing Rigali's appointment, after which Montalvo escorted Rigali to the carved wooden throne, or cathedra, that symbolizes Rigali's new authority over the archdiocese's 1.5 million members.
Montalvo then presented Rigali with another symbol of episcopal authority: a crozier, or curved bishop's staff.
Upon Rigali's acceptance of the ornate, gilded crozier that once belonged to Archbishop Francis Prendergast - Philadelphia's third archbishop - the installation was complete.
Watching from a special chair at the front of the sanctuary was Rigali's friend and predecessor, Cardinal Anthony J. Bevilacqua, who retired in June after 15 years as archbishop.
Bevilacqua stood and declared: "In the name of all those present here . . . and in the name of the entire church of Philadelphia . . . I welcome you, and assure you of our prayers, love and support."
Rigali served as the archbishop of St. Louis from 1994 until John Paul announced his appointment to Philadelphia on July 15. A native of Los Angeles, he spent most of his career before St. Louis in Rome, where he rose to become a member of several prominent Vatican departments, or congregations.
"I come to proclaim Jesus Christ as the son of God and savior of the world . . . and to serve in His name," Rigali announced in his homily. "And it is to you, dear brothers and sisters of this archdiocese, that I now commit my life and pastoral service."
John Paul announced late last month that he would elevate Rigali to the prestigious rank of cardinal on Oct. 21.
Cardinal Bernard Law, who resigned last year as Boston's archbishop for his mishandling of clergy sex abuse, was a surprise addition to the roster of visiting cardinals. His successor in Boston, Archbishop Sean O'Malley, was also on the steps. The two did not stand together.
A handful of protesters stood on the edge of the crowd along the parade route, holding signs advocating gay rights and married priests - their quiet presence a reminder that some local Catholics are discontented with church policy.
About 1:30 p.m., the deacons, seminarians and priests of the archdiocese began an outdoor procession to the cathedral steps, where they passed through its great bronze front doors and filed up the main aisle and to their seats.
Among the civic officials present were Pennsylvania's lieutenant governor, Katharine Baker Knoll; City Council President Anna Verna; and Attorney General Mike Fisher. Mayor Street attended the reception that followed.
Among the bishops was Bishop Wilton Gregory, president of the U.S. Conference of Catholic Bishops.
Philadelphia's other serving archbishop was also present: Archbishop Stefan Saroka, metropolitan of the Byzantine Ukrainian Archeparchy of Philadelphia, which is affiliated with Rome.
Besides Law, Cardinals William Keeler of Baltimore, Roger Mahony of Los Angeles and Theodore McCarrick of Washington attended, along with Cardinal Jan Schotte of the Vatican.
During both the processional and recessional, Bevilacqua was the very last in line, the position of honor. He smiled and waved at bystanders who greeted him with applause.
"He'll be missed," said Libby Franklin of St. Mary Magdalen Parish in Media, who described Bevilacqua as a "wonderful leader, priest, and cardinal."
She added that the archdiocese had been "blessed by the appointment of Archbishop Rigali. I think he's a very holy man, and that's what we need."
Rigali appeared genuinely moved at the lengthy applause that greeted him at the close of the installation ceremony.
He was chief celebrant of the Mass that followed, and gave communion to Bevilacqua before moving to the altar rail, where he gave communion to about 40 lay people and religious.
At the close of the service, he gave thanks to all those who had prepared the elaborate ceremony. He was about to move to the altar for the start of the recessional when the church suddenly filled with hundreds of male voices singing "Domine Salvum Fac," St. Charles Seminary's traditional song of greeting to special visitors.
"It's a special day, not just for Archbishop Rigali but a celebration of God's presence in the archdiocese," said Jim O'Neill, a third-year seminarian at St. Charles from the Diocese of Trenton, who was taking photos of the cathedral after the recessional.
Over the next several days, Archbishop Rigali will say special Masses in each of the archdiocese's six vicariates in honor of his installation.
Staff writer David O'Reilly can be reached at 215-854-5723, or at email@example.com.
Inquirer staff writer Vernon Clark contributed to this article.