The meeting, expected to draw hundreds of thousands from around the world, will be held from Sept. 22 through Sept. 27 in 2015. Pope Benedict XVI originally announced the selection of the city as host in June, months before his planned resignation was announced earlier this month.
The dates for the VIII World Meeting of Families were confirmed in a letter last month, Chaput said Monday. At a news conference, Chaput said he didn't know why the pope chose Philadelphia but that he was "deeply grateful."
"These events also become moments of grace," he said, adding that the region's Catholic community is "in need of healing and renewal" and that the church needs "to better protect children and young people."
Afterward, in an interview with The Associated Press, Chaput said revelations from a sex-abuse scandal, a pair of critical grand jury reports and two recent trials were part of his remarks about the need for healing.
"I think that is clearly what I meant to say," he said, adding that the planned meeting would be an opportunity "for everybody in the world."
In June, Benedict announced the venue during a Sunday Mass in Milan celebrating the seventh such gathering of families from around the world. The pope sent his greetings to Chaput and the Catholics "of that great city" and said he was looking forward to meeting them in 2015.
That was months before the announcement earlier this month that the 85-year-old Benedict would step down Feb. 28. That announcement also came as jurors in Philadelphia were deliberating in the landmark trial of a former Roman Catholic church official charged with conspiring to hide priest-abuse complaints and endangering children by keeping predators in ministry.
In that case, the Rev. William Lynn, a longtime official with the Philadelphia Archdiocese, was convicted of child endangerment and has been sentenced to 3 to 6 years in prison. Last month, a jury convicted a priest and teacher in the case, upholding an account from a troubled 24-year-old policeman's son that he was sexually abused as a boy by two priests and his sixth-grade teacher.
In 1979, Pope John Paul II drew gigantic crowds when he visited Philadelphia as part of his first U.S. tour as pontiff. The Archdiocese of Philadelphia is one of the biggest in the country.
Philadelphia Mayor Michael Nutter asked Chaput to send along the city's "deepest appreciation" for selecting the city as host, noting its founding on the principals of religious tolerance. He said the city would be ready for the thousands of visitors expected to attend.
"This will be one of the largest, if not the largest, event we have hosted," Nutter said.
Pennsylvania Gov. Tom Corbett said in a statement that, while he would be unable to make Monday's announcement, he has accepted Chaput's invitation to serve as the meeting's honorary co-chairman and looks forward to working closely with Chaput and Nutter in coordinating the event.