Pius XI High School under the direction of the Pallottine Fathers and the School Sisters of St. Francis, had its beginnings in September 1929 in three improvised classrooms above the old St. Anthony of Padua Church. In 1930, the building which today serves as St. Vincent Pallotti grade school opened its doors to 35 Pius XI High School students. Until 1937, only the first three years of high school curriculum were offered. Seniors spent their last year at Messmer, Mercy or Juneau High School.
On June 7, 1937, the University of Wisconsin placed Pius XI on the accredited list of state high schools. The charter class of eight seniors was graduated on June 13, 1937. Further accreditation was given to Pius XI in April 1953 when the North Central Association of Colleges and Secondary Schools added Pius XI to their list of accredited high schools.
As years passed, the ever-increasing student population necessitated larger facilities. The original section of the current building opened in September 1949. A six-story addition was completed in spring 1957. In fall 1998, new construction and renovation of existing space yielded a new library media center, chapel, office space, and multi-purpose lobby area, as well a as a new home for family and consumer education classes, and an enhanced audio-visual center, complete with a recording studio, and 11 new science labs/classrooms.
The latest addition, opened in fall of 2004, was Pius' fieldhouse, including a 1,600-seat gymnasium; practice, teaching and training space for 23 sports/57 teams; fitness and training space for students, staff, families and alumni; and community access for competitions and events.
The first principal was Sister M. Rita, OSF, who served from 1938 to 1943. Sister M. Loyola, OSF, served from 1942 to 1950 and Sister M. Beatrix, OSF, from 1950 to 1956. The first Pallottine Father to become principal was Father John Becker, SAC, who served from 1956 to 1964. Father Lawrence W. McCall, SAC, served as principal from 1964 to 1990. Mr. Edward Drexler served as acting principal for the 1990-'91 school year. Mr. John Halupka followed him from 1991 until his death in 1997. Mr. Richard Pendergast served as principal from 1997 to 2006. Dr. Melinda Skrade, a social science teacher at Pius for 19 years, was selected to serve as principal in 2006.