In the coming days ringing bells will herald the return of the more than 46,000 schoolchildren who are beginning their academic year at the 96 Catholic elementary schools and 34 Catholic high schools in the archdiocese.

“We are the ninth largest Catholic school system in the country. We are one of the oldest and we have always been one of the strongest in the country,” said Mary Grassa O’Neill, who this summer assumed leadership of the archdiocesan schools as Cardinal Seán P. O’Malley’s Superintendent of Schools and Secretary of Catholic Education Services.

“When I first met with the cardinal, he told me: ‘Right now, we have a system of schools. What I want is a school system,’” said Grassa O’Neill, who spent the previous five years at the Harvard University Graduate School of Education. Her most recent position at HGSE was as the managing director of the Principals’ Center and Programs in Professional Education. A former school teacher, Grassa O’Neill was the superintendent of the Milton Public School system for 10 years prior to joining HGSE.

The cardinal wants to provide the schoolchildren with not only an excellent education, but also a strong program of faith formation and a strong Catholic identity, she said.

There is a special concern the cardinal has for the schoolchildren of the poor and the inner city, she said. “He is very passionate in his concern for them.”

Grassa O’Neill said she attended the St. Ann School in Dorchester for grades one through eight and went to South Boston’s Cardinal Cushing High School. “Being in this job has really reminded me of the benefits I received from my Catholic education.”

At Cushing High, Grassa O’Neill said she was active in the glee club and intramural basketball, but the most important aspect of her time there was participation in a partnership program the school had with Harvard University.

“It was a great program run by Sister Agnes Paula, of the Sisters of Notre Dame, who later went to St. Gregory’s, where she did the same thing,” she said.

The value of her Catholic education was pointed out to her early in her career, Grassa O’Neil said. While teaching a graduate course at a state college, one of her colleagues came up to her and told her: “You went to parochial schools, didn’t you?” she said. “I asked: ‘How do you know?’ and he told me he could tell from my thought process, how I present ideas and by how clearly I explain things.”

One of the goals for the school system is to strengthen the intellectual vigor of the curriculum and introduce more testing of students, she said. In an effort to improve the professional development available for the teachers, this summer local Catholic colleges and universities, such as Regis College and Stonehill College, offered programs for teachers of the archdiocese.

As the school year begins, Grassa O’Neill said she is visiting school sites and meeting with teachers. She met Aug. 26 with more than 100 new teachers at an orientation held at Braintree’s Archdiocesan Pastoral Center. “Many of them are young teachers and some of them are more experienced coming from other programs. But, they all have a passionate commitment to making a difference in the lives of these kids.”

The following day she visited with students and teachers at North Cambridge Catholic High School and South Boston’s Gate of Heaven Elementary School.

Grassa O’Neill said she was especially excited about the opening of the Pope John Paul II Academy in Dorchester and Mattapan. “I went to the site at the old St. Margaret School in Dorchester in my hard hat and sneakers. Everyone was so excited and wondering [if it] will be ready to open on time.”

The academy, which combines seven Dorchester and Mattapan parish schools, will open Sept. 8 at five campuses with more than 1,500 students. The enrollment is an increase of almost 200 students from the total of the seven schools at the end of the last school year.

The new head of Boston Catholic Schools said she is well aware of the challenges ahead and the burden of leading such a prominent system in Catholic education.

“If I believe what everyone is telling me, everyone is watching to see what happens here in Boston,” Grassa O’Neill said.