Modeled in a combination of Spanish and French Baroque and Rococo styles, the theatre was designed to resemble opera houses and palaces of Europe of the 17th and 18th centuries.

Many of the furnishings and fixtures were supplied by Marshall Field's in Chicago and included immense Czechoslovakian crystal chandeliers of the finest quality.

It was operated at that time by Loew's Corporation as primarily a showcase for "Blacksploitation" films such as the "Super Fly" series.

In a landmark court decision, a judge blocked Loew's from removing the contents, including chandeliers, furniture, organ and projection equipment.

The building, which could be considered a very high-profile political football, came under the watchful eye of then Comptroller George O'Connell, for whom the theatre was later surnamed.

The Friends of the Buffalo were then given operating privileges of the building and undertook massive restoration through government grants and developed a performance series in the late 1970s.

The theatre is a hugely successful performance center, having undergone a large expansion of its stage facilities to accommodate larger touring productions.

Performers at Shea's from New York and southern Ontario have included The Ink Spots in 1939, Frank Sinatra for six nights in 1941, Ella Fitzgerald in 1945, Foreigner in 1977, Toronto in 1980, Blue Öyster Cult in 1984, INXS 1985, 10,000 Maniacs in 1988, Eddie Money in 1988, Liza Minnelli in 1992, Peter, Paul and Mary in 1993, Toronto's Barenaked Ladies in 1994, Buffalo's Goo Goo Dolls in 1995, 1999 and 2018; Toronto's Our Lady Peace in 1998, and Ontario's Gordon Lightfoot in 2008, composer Andrew Lloyd Webber in 2009, Rob Base and DJ E-Z Rock with Kurtis Blow and Salt N Pepa in 2011, Public Enemy in 2012, Jerry Seinfeld in 2013, comedian Bill Maher in 2015, Mary J. Blige in 2015, and Steely Dan in 2017.

[4] Performers at Shea's also include Impractical Jokers in 2018, Mariah Carey in 2019, Chris Rock in 2022, and Adam Sandler in 2023.

Built originally to provide silent film accompaniment, like many of the thousands of instruments like it, fell into disrepair, rarely being heard in the 1940s, and 1950s.