The theatre was founded by the distinguished opera director and singing coach Enrica Clay Dillon in 1936 and is now owned and operated by the non-profit Deertrees Foundation.

"[citation needed] Designed in the Adirondack style by Harrison G. Wiseman and built by George Locke of Bridgton, the theatre was constructed of rose hemlock harvested on the property.

The building was designed so the entire auditorium with its pitched floor could be detached from the stage end and moved forward allowing an extra section with more seating inserted.

More than sixty years after the theatre first opened, Christopher Hyde, classical music critic for the Maine Sunday Telegram, theorized that the tight sheathing of rough hemlock and pre-stressed posts and beams created the effect of a large stringed instrument able to transmit vibrations efficiently without echoes or reverberation.

"[5] Blau imported an entire Broadway cast from New York City every week including such stars as Ethel Barrymore, Tallulah Bankhead, Edward Everett Horton, Dame May Whitty, and Rudy Vallée.

She inaugurated The Deertrees Opera Company with the young Edwin McArthur (later replaced by Karl Kritz) as musical director and George Wells as scenic and lighting designer.

The company consisted of some 12 to 15 young singers including Astrid Varnay, Phila Tharpe, and Elizabeth Caron and was a forerunner to the great opera-training programs to come to America some fifty years later.

Mr. Harris ran Deertrees as an Equity repertory company, assembling casts from Broadway and Hollywood that included Peggy Allenby, Helene Reynolds, Margot Stevenson, Ferdi Hoffman, and William Tregoe.

The company presented mostly light comedies and farces such as For Love or Money and Petticoat Fever but the schedule also included dramatic productions of The Heiress, The Glass Menagerie, and Payment Deferred.

"Schultzy" Davis opened the season in Everybody Loves Opal while Shirley Knight, rock idol Fabian, Allen Case, and John Saxon were some of the other performers making appearances.

Fortunately, a group of concerned citizens led by Dr. Al Mills and Sally MacAuslan undertook the rescue of the theatre and formed the Deertrees Foundation to restore the building and grounds.