St. Leo the Great Parish in New Orleans was officially established in 1920. Prior to the construction of the church building, the parish community worshiped in a chapel car for approximately nine months. The first Mass in the newly built church was celebrated later that same year .​

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The school's mission is to educate each student to achieve academically, spiritually, morally, and socially, allowing them to reach their full potential. As a Catholic community, the school strives to serve each other and the school family, committing to develop mutual respect between home, school, and community for the betterment of all students.

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​In 2008, St. Leo the Great Parish merged with St. Raymond Parish to form the St. Raymond–St. Leo the Great Parish. The combined congregation continues to worship at the original St. Leo the Great Church located at 2916 Paris Avenue in New Orleans .​