Hosting this event was a huge undertaking for the Diocese of Buffalo. It required multiple sites and the involvement of virtually every priest in the Diocese, as well as laity, public officials and many others. In all, 28 committees were established to plan and coordinate activities, each staffed with between five and 30 priests. Committees focused on everything from major duties, such as ceremonies, decorations, programs and music, to operational necessities like housing, traffic, public safety and publicity. An additional 14 committees coordinated the events planned for Niagara Falls. In spiritual preparation for the congress, each parish in the Diocese was assigned a specific day where parishioners continually recited the rosary for 24 hours.

Clergy and church hierarchy came from far and wide for the event. Seven cardinals, 13 archbishops and 43 bishops attended, representing all six populated continents: North America (U.S. and Canada), South America (Bolivia, Brazil, and Peru), Europe (Denmark, England, and Sweden), Asia (China and India), Africa (Gold Coast, Sudan, and Uganda) and Australia. There were 41 cardinals and bishops from the United States representing 33 dioceses; the eight attending from Canada represented an additional seven dioceses.

A crowd of 65,000 was on hand to welcome the Archbishop of New York and honorary head of the congress, Francis Cardinal Spellman, as he and two cardinals from South America arrived at Buffalo’s Central Terminal from New York City. Crowds then lined the motorcade route along Fillmore Avenue, Humboldt Parkway, Delaware Park and Delaware Avenue as it traveled to St. Joseph’s New Cathedral at Delaware and West Utica.

On Sunday, September 21, Buffalo’s Bishop John O’Hara, the host and president for the congress, celebrated a pre-congress Solemn High Mass at St. Bonaventure University. The congress then ran from Monday, September 22, through Friday, September 26. Memorial Auditorium hosted the congress’ mission-related exhibits and activities for the 53 mission societies that participated, ranging from the Sisters of Charity to the Society of African Missions. Exhibits, movies, and lectures were offered daily. A different region of the Diocese was scheduled for attendance each day, with elementary school students attending in the afternoon and high school students in the evening. Additional exhibits were set up at the Masten Avenue Armory that were open to the public.

The Congress officially opened on Monday evening at St. Joseph’s New Cathedral with a liturgical reception for Cardinal Spellman, followed by a civic reception at Kleinman’s Music Hall, where the cardinal was welcomed by Mayor Bernard Dowd and others. The Buffalo Philharmonic Orchestra performed and every seat in the main auditorium and balcony was filled, while an overflow crowd heard the proceedings via the public address system in the Mary Seaton Room.

Tuesday morning featured a public Pontifical Mass held at Civic Stadium (later known as War Memorial Stadium). This is a solemn High Mass celebrated by a bishop, which follows prescribed ceremonies and involves the wearing of special vestments (including robes, headdress and gloves, among other articles). This particular Mass was celebrated jointly by Cardinal Spellman and the Most Reverand Amleto Giovanni Cicognani, the Apostolic Delegate to the U.S., who was directly appointed by the pope to act as his representative. The Pittsburgh Press reported that “20,000 Catholics sat in silence in sub-normal temperatures and a biting wind” for Cardinal Spellman’s sermon.

Much of Tuesday was devoted to sectional meetings for separate groups of the laity and religious, held at various local venues, including the hotels Statler and Lafayette as well as Memorial Auditorium. Tuesday also included a Pontifical Vespers service—a service of prayers said in the late afternoon or early evening—at Civic Stadium. With Archbishop John Gualbert Cardinal Guevara of Lima, Peru, presiding, the majority in attendance were high school and primary school students.

Memorial Auditorium was the site of the General Assembly, where Monsignor Fulton J. Sheen addressed a standing-room-only crowd after being welcomed with a standing ovation. Sheen was a noted radio and television personality who, between 1930 and 1950, hosted an evening radio show called "The Catholic Hour" on NBC Radio. Later, he hosted "Life is Worth Living" on NBC television. He twice won an Emmy Award as the “Most Outstanding Television Personality” and was once featured on the cover of Time magazine. In the 1960s, he hosted a syndicated television show called "The Fulton Sheen Program"His career also included serving as Auxiliary Bishop of the Archdiocese of New York and as Bishop of Rochester.

The third Mass of the day was held at Hyde Park Stadium in Niagara Falls, where 20,000 gathered for a Pontifical Mass. Archbishop Samuel Cardinal Stritch of Chicago presided, while Archbishop James Cardinal McGuigan of Toronto acted as celebrant and Archbishop Bernard Cardinal Griffin of Westminster, England, as homilist. With the stadium full, thousands more lined the nearby streets.

Fifteen section meetings and Holy Hours were held throughout Wednesday afternoon and evening. A session for mothers at Memorial Auditorium drew 14,000 people and was followed by a Holy Hour. One for religious sisters was held at St. Stanislaus Church, where the rector of Catholic University in Washington, DC, spoke to the over 1,000 attendees. A session for priests held at Canisius High School was led by Cardinal Stritch and Bishop Thomas Malloy of Brooklyn. A Holy Hour followed. Working men assembled at Civic Stadium. While precedent called for a single cardinal to address an audience, tradition was broken in consideration of the significance of the audience to Catholic homes and families. Instead, four cardinals spoke: Cardinals Spellman, Griffin and McGuigan, along with Cardinal Gilroy of Sydney, Australia. The Hon. Joseph P. Kennedy, former ambassador to England (and father of the future president), also spoke.

Smaller sessions were held at various locations in the Hotel Statler and included farmers, lawyers, bankers and businessmen, as well as college students and physicians. These were led by bishops from across the country and Canada, and several featured speakers from outside the clergy. Judge Charles Desmond of the New York State Court of Appeals spoke to the session of lawyers, while John Moody, board chairman of Moody’s Investors of New York, and M.E. Coyle, executive vice-president of General Motors, addressed the group of businessmen and bankers. The presidents of Niagara University and the University of Notre Dame spoke to about 1,000 students in the Statler’s ballroom, while the surgeon-in-chief of Carney Hospital in Boston addressed the session of physicians. The working women’s Holy Hour at Memorial Auditorium drew an audience of 12,000.

Although the mission exhibits continued into Friday, Thursday was devoted to the closing ceremonies. A final Pontifical High Mass was celebrated at Civic Stadium, the highlight of which was a Human Rosary formed by the Knights of St. John, a Catholic fraternal organization that combines social and benevolent elements.

The closing session in Delaware Park, however, was said to be the largest crowd in Buffalo’s history. A Eucharistic procession marched with the Blessed Sacrament from Mount St. Joseph’s Teachers College (now Medaille College) on Agassiz Circle to Delaware Park, escorted by the Knights of St. John, Knights of Columbus and other groups, along with hundreds of priests and bishops. At the park, they were joined by representatives of parish groups, Catholic organizations, other religious personnel and seven bands as they marched along a 20-foot-wide pathway through the assembled crowd. The procession was said to contain 75,000 people and was over half a mile long. The overall crowd, including the procession, was estimated at 200,000. 

According to the Chicago Tribune, “200,000 knelt in Delaware Park and bowed their heads as Francis Cardinal Spellman, Archbishop of New York, raised a golden monstrance bearing the consecrated Host.” The monstrance, on loan from the University of Notre Dame, is believed to have been presented to the university in 1867 by Emperor Napoleon III of France.

The 1947 Eucharistic Congress in Buffalo was hailed as an outstanding success. It was widely covered by Buffalo newspapers and radio stations, as well as newspapers throughout the U.S. and Canada. An article in the Connecticut Bridgeport Telegram on September 25, 1947, provided a good summary of the event:

Hundreds of thousands flocked to five Pontifical masses and dozens of sectional meetings and holy hours in a demonstration of Roman Catholic Mass worship and ritualistic splendor unrivalled in this country since the last Congress in 1941 at Minneapolis-St. Paul.

The participants included seven cardinals, sixty-five archbishops and bishops and scores of prominent members of the clergy and laity.

The Congress brought a huge number of visitors and a great deal of attention to Buffalo. It also rejuvenated Buffalo’s Catholics, somewhat weary after 10 years of the Great Depression and more than five years of world war.