The Citadel Theatre was founded on October 10, 1965 when Joseph H. Shoctor, James L. Martin, Ralph B. MacMillan, and Sandy Mactaggart paid $100,000 for the Old Salvation Army Citadel on 102 Street, Edmonton. A further $150,000 was spent on renovations to create a theatre on the main floor and a restaurant in the basement. The Theatre's first production, Who's Afraid of Virginia Woolf?, opened on November 10, 1965 under the guidance of founding Artistic Director John Hulbert and General Manager Olive Finland, who served in that capacity until 1976. The founding Board of Directors consisted of:

In 1968, Sean Mulcahy became Artistic Director and oversaw the creation of Citadel on Wheels, a program designed to tour schools and communities throughout northern Alberta, and community drama classes which became the basis for the Foote Theatre School.

In 1973, John Neville took over as Artistic Director and expanded Citadel offerings to include a second series for more experimental works as well as recruiting international talent to the company. Neville was also at the helm during the Citadel's expansion into its current facility, a move that was enabled by fundraising efforts, government grants, and a gift of land from the City of Edmonton. Ground was broken on the new building in December, 1974 and the facility was designed by Barton Myers Associates with R.L. Wilkin as architect.

The new Citadel Theatre complex was officially opened on November 12, 1976 and the first production in the new building, Romeo and Juliet, opened the following day. The new facility featured the Shoctor Theatre (a proscenium stage with 681 seats), the Rice Theatre (a 200-seat theatre designed for experimental theatre with flexible seating and stage), and Zeidler Hall (a 220-seat theatre originally designed for films and lectures).

In 1978, Peter Coe took over as Artistic Director followed by Joseph Shoctor, who took control of programming in 1981 under the title of Producer. Gordon McDougall became the Artistic Director in 1984, but his appointment was questioned as he was the third British citizen appointed to the position (Coe and Neville being the previous two). McDougall oversaw the opening of Phase II of the facility, which included the Lee Pavilion, the Maclab Theatre (a thrust stage with 682 seats), and the Tucker Amphitheatre (a 150-seat theatre surrounding a reflective pool).

In 1987, William Fisher became the Artistic Director and the production season expanded to three series, three theatre school presentations, the International Children's Festival, and the Edmonton Teen Festival of the Arts. Shortly after, the final phase of the Citadel Theatre complex was completed in 1989 and included an expansion to the production shop, additional classrooms, and a complex of multi-purpose rooms for auditions and rehearsals.

After a brief period with Richard Dennison as Producer, Robin Phillips became Director General in 1990. The Citadel experienced a resurgence of innovative and controversial theatre under Phillips. Duncan McIntosh became Artistic Director in 1995 and was followed by Bob Baker in 1999, The Citadel's first Edmonton-born Artistic Director and current head.

In addition to the Artistic Director, the Citadel Theatre also has an Executive Director position, a Board of Directors, and a Board of Governors.

The fonds consists of records created, received, and solicited in the mounting of productions created by The Citadel as well as by its outreach programmes. The records are comprised of files, plans, scripts, audiovisual material, press releases, programmes, fact sheets, playbills, newspaper clippings, posters, and promotional material as well as a significant number of administrative, financial, production, and personnel files. Also included are plans, both architectural and structural, for the new theatre additions.