Brady High School was built on a 34 acre parcel of land situated on the eastern edge of West St. Paul. Its site had been part of a 65 acre land tract known as the Thompson Lake property. The Sisters of St. Joseph of Medaille had purchased the Thompson Lake property from Dr. James and Lois Reid in 1954. For several years the Sisters of St. Joseph had considered plans to use the site to build a high school for girls. In 1957 the site was sold to the archdiocese which continued to view the property as the site of a future high school, including the Sisters in its long range plans.
In 1961 the Sisters of St. Joseph committed to staffing the future high school. Plans for the new school progressed and it was founded as the first co-educational high school in the archdiocese, with staffing by both the Christian Brothers and the Sisters of St. Joseph. It was named for Archbishop William O. Brady who had died in 1961, when plans for this school were ongoing.
Brady High School opened in the fall of 1964 with 304 freshmen students. Sister Doreen Charest, CSJ, was the first principal of the girls department. Brother Hilary Gilmartin, FSC, was the school superintendent.In 1968 Brady's first class graduated. Its enrollment then exceeded 1100 students. In April of 1969 the University of Minnesota sent a team of 25 educators to evaluate the school. Their recommendation of accreditation was unanimous.
In 1972 the Christian Brothers requested that they be relieved of their responsibilities at Brady by the end of the 1972-73 school year, due to their declining membership. The Sisters of St. Joseph asked to withdraw from their articles of agreement concerning the school at the end of that same school year. At the close of the 1977-78 school year the Christian Brothers and Sisters of St. Joseph withdrew from the staff of Brady High School.
In the fall of 1978 Tom Gagliardi brought new energy to the school as Brady's principal. That year, Hank Mauer who had served Brady as a teacher and coach, became Brady's dean of students. Hank was recognized as an "adopted father and friend" to Brady High School. His untimely death in April of 1984 was a tremendous loss to the school. For a number of years, class sizes continued to drop. In the spring of 1991 the archdiocese decided to close Brady at the completion of that school year. From 1968 through 1991, approximately 3200 students graduated from Brady High School.