The original idea for a single, united students’ association at Concordia started even before the university was created in 1974 by the merger of Loyola College and Sir George Williams University (SGWU). As early as 1972 negotiations took place between the Loyola and SGWU undergraduate student associations and went on for some years before reaching a final structure. In March 1979 undergraduate students from Loyola and SGW campuses voted in a referendum and approved the formation of the Concordia-wide Students' Association, to represent all undergraduate students: Concordia University Student Association (CUSA). On April 2-5, 1979 the first election for the CUSA co-presidents and legislative council was held. Agop der Khatchadurian and Louis Francescutti, were the first CUSA co-presidents.
In a referendum held in March 1982, students voted for incorporation in principle. CUSA was incorporated by Quebec, on September 3, 1982. In March 1983, students voted 84 per cent in favour of CUSA’s new and improved by-laws, taking legal ownership of the Association from the university administration to the students. Elected officers would be accountable to the undergraduate student body, the shareholders of the corporation. In 1984, CUSACorp was created, a wholly owned subsidiary of CUSA whose sole purpose was to provide and run student entertainment services at Concordia, namely the Loyola Campus Centre and Reggie’s Pub on the downtown campus.
In March 1994, undergraduate students agreed in a referendum to change the name of CUSA to the Concordia Student Union (CSU), and additionally supported several restructuring motions. A major change saw the replacement of the co-president system with the election of a single CSU president. In April 1994, Marika Giles was elected as the first CSU president.
On March 29-30, 2000 undergraduate students voted in a referendum to end the appointment of the CSU vice-presidents. Starting in 2001, all presidential candidates would run for office with a slate of vice-presidents, ending over 20 years of their being appointed after the general elections.

Concordia Student Union has been publishing, at the beginning of every academic year, the CSU Student Handbook.