Established in 1862 by the Congregation of Christian Brothers, the school moved to its current site in Summerhill in 1970.

[1] The school was founded by the Congregation of Christian Brothers (CBS) in 1862 at John's Lane before moving to its current campus at Summerhill in Nenagh in 1970.

[2] The school shares its current campus with Nenagh CBS Primary School, and enrols boys from a wide catchment area in the local area and beyond.

The ethos aims at promoting "full and harmonious development of all aspects of the person of the pupil", "a living relationship with God and with other people", "philosophy of life inspired by belief in God and in the life", "death and resurrection of Jesus" and "the formation of the pupils in the Catholic faith".

[4] The school promotes certain religious values, and as such may refuse to admit a boy who is not of the Catholic faith and it is deemed that the refusal of boy concerned is essential for the maintenance and upholding of the ethos of the school.