Once described as "the nicest guy in the Vatican" by the National Catholic Reporter, Cardinal Foley had suffered in recent years from leukemia. He died at Villa St. Joseph, the archdiocesan home for retired priests in Darby, the town where he was born.
Citing fatigue and declining health, he returned to the archdiocese in February after four years as Grand Master of the Equestrian Order of the Holy Sepulchre of Jerusalem, a papal knighthood based in Rome.
For the previous 23 years, he had served as first president of the Pontifical Council for Social Communications, with particular responsibility for explaining church teachings to electronic news media.
When he stepped down from the council in 2007, the year he was made cardinal, he was the longest-serving head of any major office in the Vatican.
"I was pleased he was able to come home during the final months of his life," Philadelphia Archbishop Charles J. Chaput said Sunday from Rome. "No matter where he lived or how he served the church over the years, he always considered Philadelphia his home."
Funeral arrangements were not announced, although a Mass at the Cathedral Basilica of SS. Peter and Paul was expected.
Chaput was in Rome for a regularly scheduled series of meetings between diocesan bishops and Pope Benedict XVI. The archbishop asked the people of the archdiocese to pray for Cardinal Foley, and for his priests to say Masses for him.
Cardinal Foley was perhaps best known to American audiences as host for 25 years of NBC's annual broadcast of the papal Christmas Mass at St. Peter's Basilica.
The council presidency "was never a career," Cardinal Foley said during a 2007 interview in Rome. "It was always a vocation, responding to what God calls you to do."
While in Rome he lived in a plain, two-room apartment at the Villa Stritch, a residence for American clergy, where he answered his own phone.