Finally, it moved into offices in the Broadway Theater Center in Milwaukee's Historic Third Ward and remained there until its collapse.
Much of its early work was created improvisationally as an ensemble, with influences including The Living Theatre and Jerzy Grotowski.
This move away from an ensemble structure led to a public dispute when the board gave ensemble members John Kishline, Deborah Clifton and Marcie Hoffmann a forced leave of absence from acting in hopes of re-structuring the company, leaving only Schneider and Flora Coker as the remaining founding members.
Willem Dafoe was an early member of the ensemble and, when he stayed in New York to eventually join the Wooster Group, was replaced by Victor DeLorenzo, who later was one of the founders of Violent Femmes.
John Sobczak, Cate Woodruff (then Pamela C. Woodruff) and Wesley Savick were also long-time members of Theatre X. Lory Lazarus, a member of Theatre X in the mid 1970s, went on to become a writer for Cartoon Network's "Courage, the Cowardly Dog" and a songwriter for "Barney & Friends" on PBS.