Roncalli High School is an interparochial archdiocesan Catholic high school. The term interparochial refers to the fact that the school receives financial and pastoral support, along with the majority of its students, from the 14 parishes that comprise the South Deanery of the Indianapolis Archdiocese. The school is named Roncalli in honor of Cardinal Angelo Roncalli, who, upon being elected pope by the College of Cardinals in 1958, took the name of Pope John XXIII. Blessed Pope John was canonized a Saint on April 27, 2014 and is now known as Saint John XXIII.

Roncalli has three times - 1993, 1998, and 2003 - been recognized by the U.S. Department of Education as a Blue Ribbon School of Excellence.