Keach played the title role in "MacBird!", an Off-Broadway anti-war satire by Barbara Garson staged at the Village Gate in 1966. In 1967, he was cast, again Off-Broadway, in George Tabori's "The Niggerlovers" with Morgan Freeman in his acting debut. To this day, Freeman credits Keach with teaching him the most about acting. In 1967, Keach also starred in "We Bombed in New Haven," a play by Joseph Heller that premiered in New Haven at the Yale Repertory Theatre and later was produced on Broadway. Keach first appeared on Broadway in 1969 as Buffalo Bill in "Indians" by Arthur Kopit. Early in his career, he was credited as Stacy Keach, Jr. to distinguish himself from his father. He played the lead actor in "The Nude Paper Sermon", an avant-garde musical theatre piece for media presentation, commissioned by Nonesuch Records by composer Eric Salzman.