The building located at 450 Post Street was built in 1924 by the Benevolent and Protective Order of Elks in order to accommodate a burgeoning membership. Using the designs of architect Anthony Heinsberger, whose theatrical architecture can also be seen at the Paramount Theatre in Oakland and at the Orpheum Theatre in San Francisco, the entire 15-story structure was built at a cost $1.5 million dollars. The building is of Spanish-Gothic design and originally contained 100 hotel rooms (now the Kensington Park Hotel) for resident members and visiting Elks. The second floor main Lodge assembly hall (now Post Street Theatre) was designed to have a seating capacity of 1,000, a projection room, maple stage and theatre pipe organ.
In 1981 the BPOE leased the building to various partners, creating a hotel, shops, and other spaces. At that time the second floor Lodge hall became Theatre on the Square where it was redesigned by architect Gene Angell. The flat-floored assembly hall was transformed into the 729-seat theatre as you see it today.
When Theatre On The Square vacated the space in 2002, Messrs. Nederlander accepted the invitation to assume management of the theatre. Working with Gensler Architects, who designed the handsome remodel of the Geary Theatre, improvements were set in motion to do a cosmetic update of the theatre.