In 1968, Bill Russo performed his musical work, The Civil War, at Notre Dame University in Indiana, which consisted of four numbers built around Pulitzer Prize winner Paul Horgan's text. Students asked if they could add a light show to the performance and Russo wrote additional music for the choral singers, thus marking his first 'rock cantata'

The new Civil War combines a rock musical score, slides depicting war, and solo and chorus singers. It debuted in San Antonio, TX on April 7, 1968, the day after Dr. Martin Luther King, Jr., was killed and the opening performance was dedicated to him. The Civil War held additional performances in New York City, New York, and then began a run of performances at The Theater, 1848 Wells Street, Chicago.

From its second Chicago performance , the theater was filled to capacity, and the Free Theater was born. Its business model - donate what one could to view a performance, as no admission fee was charged. There were no auditions for performances; people who wanted to be part of the experience found a role in the theater. Over its years of operation, the Free Theater resided in seven places, including an old Chicago bowling alley.

Other Free Theater performances include: David, City in a Swamp, Urbs in Hortis, Ages of Man, Breathe Deeply, Today Is ________ (fill in the blank), The Bacchae, Mass, Aesop's Fables, and others. It also held an ongoing Improvisation Ensemble workshop weekly.

The Free Theater closed in 1973, with theatrical productions operating solely through the Columbia College Center for New Music department, established by William Russo in 1965 at the college.