The school was named after Senator Frank O'Connor, founder of the Laura Secord chocolate company.

[4] O'Connor was appointed to the Senate of Canada in 1935 by Liberal Prime Minister William Lyon Mackenzie King.

The high school was built on land given to them by Senator Frank Patrick O'Connor, a Catholic philanthropist and founder of Laura Secord Chocolates, a Canadian chocolatier and ice cream company.

The Christian Brothers' house was located in the center of the campus, and so students would pass right in front of it or around it on all sides daily.

In 2002, the Toronto Catholic District School Board acquired the O'Connor House from the Christian Brothers.

The old Lynch, O'Connor and Taj Mahal buildings were demolished and a large new modern two-storey 1020-pupil high school which opened in September 2005 is now in place.

The address change occurred because the entrance to the school was moved to the opposite end of the property that opens onto Rowena Drive.

Senator O'Connor celebrated its 50th anniversary on June 1, 2013, with a mass and the opening ceremonies, including a presentation to Brother Domenic Viggiani, president of De La Salle College, who accepted plaques on behalf of the school's founding Christian Brothers, some of whom also attended the event.

[7] The Advanced Placement program continues a tradition of achievement, by providing students with the opportunity for academic enrichment.

At Senator O’Connor, a select cohort of students studies at the AP (Enriched) level in Core Courses from the 9th through 12th grades.

Writing AP College Board exams at the end of Grade 12 can lead to the acquisition of equivalent credits in participating universities in Canada, the United States and overseas.