St. John School began as a log cabin school staffed by the Sisters of Mercy in 1867. Notre Dame Seminary for Girls was the original high school. The seminary building was destroyed by fire in 1923. After three years of rebuilding, St. John Elementary and High School opened in 1926. Additions in 1954 and 1962 have increased SJS to its present structure. The high school celebrated its centennial in 1985 and graduated its last class in 1989.