Bishop Reding was founded in 1986. Its namesake is Bishop
Paul Francis Reding, Bishop of the Hamilton Diocese for ten years and an ardent defender of Catholic education. The school was the first Catholic high school for Northern Halton. In 1994, the school participated in a 25-year HCDSB time capsule project, opened in 2019. In 2002, many of Bishop Reding's students were transferred to the new school in Halton Hills,
Christ the King Catholic Secondary School, a change commemorated with a plaque in the BR Trophy Case. Similarly, in 2013, many BR students were redistricted due to a population swell in Milton, to
St. Francis Xavier Catholic Secondary School.
Milton MPP and
Wynne Government Education Minister,
Indira Naidoo-Harris, announced an $18 million extension to BR that would cut the number of portable classrooms down from 43 to 27, by the 2020–2021 school year. After it was temporarily cancelled by the
Ford Government, Milton MPP
Parm Gill announced that funding would be reallocated for the Bishop Reding expansion. Bishop Reding has been noted for their student involvement, holding walkouts protesting both the controversial HCDSB Sanctity of Life motion, organized by student leaders Karyssa Chan, Margaret Manangan, and Ashwini Selvakumaran, and the Ford Government's cuts to education and
OSAP. ==Athletics==