The school was named after David and Mary Thomson, the first European settlers who immigrated to Scarborough in the late 18th century.

2 (the forerunner of the Scarborough Board of Education and later the Toronto District School Board) acquired 8.6 acres of land on Lawrence Avenue East west of Brimley Road for the future secondary school known as David and Mary Thomson Collegiate Institute splitting off the population of Winston Churchill Collegiate Institute and R. H. King Collegiate Institute and expanded later to six acres.

The school underwent additions in the 1960s and 1970s including extra classrooms, new gymnasia for girls and boys, science labs, an enlarged library, and vocational shops.

In June 2000, Midland Avenue Collegiate Institute was closed; students in its former catchment area are now served by Thomson.

On February 4, 2009, The Toronto District School Board approved a plan to merge David and Mary Thomson with the neighbouring Bendale Business and Technical Institute to form a modern "superschool".

[8] In June 2012 the Toronto Lands Corporation declared the Thomson site (12.3 acres) and building surplus.

Various boards and public bodies expressed an interest in buying the property, including the Toronto Catholic District School Board,[9] Conseil Scolaire Viamonde and Conseil scolaire de district catholique Centre-Sud.

The motto appears at the base of a scarlet maple leaf on which are superimposed a lamp of learning and the initials D and M in white.

The leaf is flanked by a large "C" and "I", both in black forming arcs of a circle with the lower sections of the motto.

Finally the name "Thomson", white on a scarlet background, surmounts the rest of the design and completes the circle.

David and Mary Thomson Collegiate Institute is a four-storey composite high school on 12 acres of land.

The new school contains 48 conventional academic classrooms, seven science labs, five computer labs, two music rooms, one theatre arts room that can be used as a lecture hall, two gymnasia that can be partitioned into two smaller gyms, main and guidance offices, a library, a centralized cafetorium with a stage, six special education classes, four vocational shops and labs for woodworking, culinary, green industries and hairstyling and six staff workrooms.