St John's Prep was originally founded in 1907 by a group of Xaverian brothers.

[3] It became evident in those early years that enrollment would continue to rise, so in the spring of 1910 construction began on Xavier Hall.

St. John's Preparatory school is located in the town of Danvers, Massachusetts, about 20 miles (32 km) north of Boston.

The student population spends the majority of its time in the four main academic buildings: Other buildings of note include: Also on the property of St. John's are two homes for Xaverian Brothers: St. John's Prep is a member of the Massachusetts Athletic Association's (MIAA) Catholic Conference.

The Prep's alpine ski team won three straight state titles in a row entering the 2024-25 school year,[3] while the lacrosse program captured the last four state titles through 2024.