Catholic education has served Aberdeen for nearly 125 years.  The first Catholic school was established inside Sacred Heart Church in 1886, and a freestanding school was built a few years later.

St. Mary's and Sacred Heart parishes each built elementary school buildings, serving grades 1 through 8, in 1912 and 1913 respectively. The Benedictine and Presentation Sisters were the primary teachers in the schools for many decades. Roncalli High School was established in 1964. Roncalli Junior High, grades 7 and 8, was established in 1969 at Sacred Heart School. In 1988, those students moved to the high school, which became Roncalli Junior/Senior High School.

In 1980, the Aberdeen Catholic School System was consolidated and Sacred Heart and St. Mary's Schools were renamed Roncalli. Kindergarten was also added to the educational program. In 1988-89 school year, the Roncalli Sonshine Patch-DayCare Program was created.  In 2002-2004, ACSS demolished its elementary buildings and built Roncalli Primary School (preK-2) and Roncalli Elementary School (3-6).

Roncalli is the family name of Pope John XXIII who captured the imagination of the entire world, and changed the hearts of millions in a short space of time.  Elected Pope on October 28, 1958, he was expected to be only an "interim" pope, but he changed the course of modern Christianity by summoning the Second Vatican Council to deal specifically with the question of Christian unity. Under his leadership, many sweeping changes were made to help the church meet the challenges of modern times. In 1964, the name selection committee felt that the new high school, Roncalli, should be dedicated to the same objective as that of Pope John XXIII, by assisting the Catholic students of Aberdeen to meet the challenge of the modern time...educationally, socially and spiritually.

Statement of Mission

Sioux Falls Catholic Diocese 
The Bishop's Pastoral, To Teach as Jesus Did, largely sets the tone for Catholic education today. 

The pastoral reminds us that Catholic schools offer the greatest opportunity to teach the message of Jesus Christ, to foster a community of believers who grown in the faith, and to provide for Christian service to the community

Catholic education is an expression of the mission entrusted by Jesus to the Church he founded. Through education the Church seeks to prepare its members to proclaim the Good News and to translate this proclamation into action.

The educational mission endorsed by the Sioux Falls Catholic Diocese is an integrated ministry embracing three interlocking dimensions: the "message" revealed by Jesus which the Church proclaims; "community" in the life of the Holy Spirit; and "service" to the entire human community. All who share in the responsibility for educational ministry must support programs which give promise of realizing this threefold purpose, which is the guide and inspiration of all the Church's educational efforts.

Aberdeen Catholic School System 
Until the 2000 - 2001 school year, the ACSS held, "To Teach As Jesus Did," as its primary mission statement. During the 2001-2002 school year, the ACSS began a process of discernment and school improvement which included an in depth analysis of 'who we are' and 'what we believe'. Pastors, Teachers, auxiliary staff, students, parents and community members were involved in this process. From this introspective study, a new mission emerged: 

“Instilling Catholic values and promoting academic excellence by nurturing mind, body and soul.”

This mission complements the previous mission, which is still a part of our charism. To Teach as Jesus Did is a call to our staff, parents and community as to how we are to teach. The goal of our teaching is expressed in the ‘new’mission statement. Thus, as we strive To Teach as Jesus Did, our goal is Instilling Catholic values and promoting academic excellence by nurturing mind, body and soul.