The Keswick Theatre first opened its doors on Christmas Night, 1928. Nationally recognized as the most comfortable, acoustically perfect listening room in the entire Philadelphia market, the Keswick was designed by acclaimed architect Horace Trumbauer (who also created the Phila. Museum of Art). Initially a combination vaudeville/movie house, the Keswick hosted such legends as Stepin' Fetchit, Paul Robeson and Ina Ray Hutton (Betty's sister) with her all-girl band. In 1955, the theater was remodeled into a cineamascope film house, hosting the area's premiere releases of most of the big-budget movies of the 1950s and '60s. In Spring 1980, the Keswick closed its doors as a movie theater, slated for demolition. The Glenside Landmarks Society, a not-for-profit group, formed with the hope of restoring it to its former grandeur to operate as a performing arts center. It re-opened in 1981 with a sold-out concert by Fred Waring and the Young Pennsylvanians.

Over the next four years, stars like Roberta Peters, Carlos Montoya, Theodore Bikel, Buddy Rich, Lionel Hampton and the Preservation Hall Jazz Band graced the stage. The Keswick was placed on the National Register of Historic Places in 1983, but the non-profit group wasn't to meet expenses, and closed the theater in December 1985.The Keswick opened its doors again in March 1988, under private ownership. They successfully tackled problems associated with older buildings, drastically increased the activity at the theater, and successfully established the Keswick in the eyes of the public. During that 15-year ownership, the Keswick blossomed in reputation and renovation. Establishment of a restoration fund allowed for more than a million dollars in upgrades, including extensive updates in electrical and heating/ventilation systems, reupholstering seats, roof replacement and repair, extensive facade repair, and restoration of the original ornamental plaster.

The Keswick grew technologically, as well, with state-of-the-art sound and light equipment and a computerized ticketing system. This growth was recognized, as the Keswick joined legendary venues like The Chicago Theatre, Beacon Theatre and Fox Theatre in "Pollstar's Top 50 Theater Venues." The Keswick became one of the Central Atlantic states' most active and diversified venues, presenting internationally acclaimed performers geared to virtually every taste and interest. The Keswick also hosts approximately three dozen shows annually to introduce school children to live theater, and serves as a destination for community events with dance recitals, graduations and other functions.