In late 1930s, Chicago Jesuits were requested by popular political figures of the time to establish a premier educational institution for boys in city of Patna. On January 17, 1940, St. Xavier's was founded with Fr. Marshall D. Moran S.J as its first principal.

Over the years, Xaverians have excelled in a variety of areas both in India and abroad. St Xavier's School has an excellent facities of sports also. It has a beautiful swimming pool with diving board, a basketball court, a tennis court, table tennis room, a handball court.
The school changed from Senior Cambridge to Bihar Board, when the Jesuit fathers took over St. Michael's School from Irish Christian Brothers in 1968. After being a school for boys for more than 50 years, St. Xavier's turned into a co-educational institution in 1999. In the same year, ICSE was introduced as an alternate course for the students willing to go for English medium education, during the able administration of Fr. Peter Arockiasamy. Today Both ICSE and BSEB courses are run simultaneously.
The school celebrated its Diamond Jubilee in the year 2000. Interestingly, Patna Women's College, Patna and The Holy Red Cross Society, Patna celebrated their Diamond Jubillee the same year.
In year 2008, +2 has been introduced applying BSEB courseware under the guidance and able hands of the principal Fr. George Nedumattam S.