Saint Peter's Prep (the Prep) was founded by members of the Society of Jesus (the Jesuits) in 1872, and today the school is sponsored by the Jesuits of the New York Province.
The Prep, located in the historic Paulus Hook section of Jersey City, was founded as a "department" within Saint Peter's College (Saint Peter's University), along with the collegiate and grammar school departments. At the time of its inauguration as a school, the only building on the campus was Shalloe Hall at 144 Grand Street. As more students arrived, work began on a new school building on Grand and Warren Streets. Mulry Hall, on the corner of Grand and Warren Streets, was built around the turn of the century as a parish social club, before being acquired by the school.
The preparatory and grammar departments separated from the College in 1918 when the Jesuits decided to close the collegiate division with the outbreak of World War I. The collegiate department reopened in another location in 1930 and in 1936 settled at its current location on what is now called Kennedy Boulevard. The collegiate and preparatory departments were officially incorporated separately on February 10, 1955. Although Saint Peter's College has not been located at 144 Grand for over eighty years, at an entrance to the original building, Shalloe Hall, a window pane above the door still reads "Saint Peter's College."
The Prep has been in continual operation since 1872, and continues to thrive today as a Jesuit, Catholic, independent college preparatory school for boys in grades 9-12 at its original location at 144 Grand Street.