In 1965, Corpus Christi High School was expanded and renamed F.J. Brennan Catholic High School in honour of Monsignor Francis J. Brennan, a Windsor priest prominent in the Catholic educational system in Ontario.

The expansion included a glass walled weight room, a new chapel, new flooring, offices, halls, lockers, and a new cafeteria.

In Fall 2003, a 50th anniversary celebration/reunion was held in the newly renovated school where past decades of students attended.

Each year, F.J. Brennan Catholic High School and St. Joseph's Catholic High School take part in the annual Father Zakoor Cup hockey game, where this past year 2019, the F.J. Brennan Cardinals beat the St. Joseph Lasers.

The school's strengths are in academics, sports (particularly football, volleyball and hockey), and the arts (it has excellent, award-winning music and drama programs).