The building was commissioned in 1963, by Bishop John Cody, to be an institution for training of candidates entering diocesan priesthood.

Young men came from all over Canada, the United States, South & Central America, and Europe to attend.

RMC is situated on 50 acres of land, bounded by Wellington Road to the west, the London District Catholic School Board to the north, a pond and forest to the east, and Scotland Drive about 500 metres to the south.

The four-level Main Building, Three self-contained portables, two which are used by the CEC and one of which being the dance studio, a track and football field with field house, and a soccer pitch make up the entire secondary school campus.

In addition to having internet access from each classroom, the library resource center catalogs are available online to the students.

Not much is known for the other additions, they were either part of the original construction of the building, or added on in 1967, when it became a boys boarding school.

Compared to many other secondary schools in the London area, RMC has a very simple, linear layout.

The bell tower which used to be in front of the school stood directly over the main entrance, which led into this central section.

Classrooms for hospitality and tourism (foods) are located nearby to the cafeteria, as well as for family studies.

In the Central Section, the first floor holds the Administration Offices (Principal, Vice Principals, Security, Attendance, and Guidance), the upper portion of the Staff Lounge, the chapel (above the Cafeteria), offices for the school Social Worker and Chaplain, offices for Co-Operative Education, The upper Conference Room, and a small number of classrooms which are most often used for religion, and some social sciences like economics, civics and history.

For the most part, these classrooms are used for computer studies, French and other languages, and other social sciences such as law, business, and geography.

The room offers a connection to a small balcony overlooking the chapel, likely where choral performances could take place.

The library is located on the north end of the second floor, directly above the Single Gymnasium corridor.

Since the library was put on part of the original school, two support columns were added, which are in the single gym rotunda.

Included in the library is a large reading and studying space, a small computer lab for use on lunches or spare periods, and two multi-purpose rooms which can be used for presentations or meetings.

It has a vast number of free-weights, weight machines, and other exercise equipment, which are used in physical education classes.

Because the Central Section of the building is on a raised foundation to the basement, and the Technology Wing is built level to the ground, there are ramps connecting the basement and first floors of the Central Section to the first and second floors of the Technology Wing, respectively.

It used to be the ARMO Hall (Association of Regina Mundi Old Boys), thus there was previously dorms in that wing.

The chapel at Regina Mundi is located on the first floor of the Central Section, and is visible as soon as one walks into the main entrance of the building.

The chapel is built of stone on the exterior, as is the rest of the school, and has a wood finish inside.

Along the entire chapel are stained glass windows, and images featuring the Stations of the Cross.

To either side of the cross are long fabric drapes displaying the school's colors of blue and gold.

The chapel also features the Memory Wall, which has pictures of all the students and staff who have died during their terms at RMC.

By March 1, 2011, the tower had been completely dismantled, and the cross was replaced atop the roof of the Central Section of the Main Building.