The Square One Theatre Company, a non-profit theatre, was founded in 1990 by Barbara Cairney and Tom Holehan. The two had worked together at the American Shakespeare Theatre and saw an opportunity to create a professional theatre in Stratford when the town's former movie house was bought and renovated as a stage theatre by a private organization. After negotiations with the new owners, a staff was organized from former Shakespeare Theatre people, an advisory board of directors was created and funds were raised from area communities. An organization, The Friends of Square One, was also established and serves as the volunteer arm of the theatre directly assisting all behind-the-scenes activities of the company. Square One's first play, Lee Blessing's A Walk in the Woods, was honored on opening night by its original producer, Lucille Lortel, and went on to win state, regional and national honors at various theatre competitions.

Square One is now in its seventeenth season. Along with critical and financial success has come support from greater New Haven and Fairfield counties as well as local businesses and corporations. This support has allowed the theatre to expand its role in the community with an educational outreach program offered to area schools. In conjunction with Square One, the nearby Stratford Library has expanded its Readers Theatre Showcase series with free readings of classic as well as new and non-commercial plays. The Milford and Orange Libraries, Atria Assisted Living and Oronoque Village have also become part of this program. The school program is made possible by a renewable grant from People's Bank. Free performances for Stratford students were inaugurated by the theatre in 1996 and continue each season. The educational program continues to grow as funding is obtained.

The theatre's eighteenth anniversary season opens on November 2, 2007 with John Patrick Shanley's Pulitzer Prize and Tony Award winning drama"Doubt".  The season will also include the beautifully observed and touching new play "Rabbit Hole" by David Lindsay-Abaire and Neil Simon's classic comedy "Last of the Red Hot Lovers".