The show, which began on March 27, and was to have closed on April 25, has extended until May 2.

Actor Andre De Shields' defection from the Goodman Theatre's staging resulted in some casting consternation for the Chicago nonprofit. De Shields, who was set to star as father Robert, left that production in order to honor a previous commitment to appear in Mark Medoff's Prymate, which is due on Broadway. He was replaced by John H. Cochran. Cochran was then replaced by Phillip Edward VanLear. Cochran is continuing as understudy to the role.

VanLear will play Robert, the brilliant but mentally unbalanced mathematician who counsels his troubled daughter Catherine, who may or may not have inherited her dad's genius, as well as his instability.

Playing the daughter is Karen Aldridge. Catherine's sister Claire is portrayed by Ora Jones, and Dwain Perry is Hal, Catherine's timid suitor. The entire cast for the play is African-American—something sought by the Chuck Smith from the time the title was scheduled. The show is thought to be the first all-black professional staging of the play.

Proof began life at Manhattan Theatre Club in 2000. It then transferred to Broadway, where it ran for more than two years and won the Tony Award for Best Play and Pulitzer Prize.