Kostroff is an active member of the Musical Theatre Guild, a Los Angeles-based theatre company that performs rarely-seen musicals, where he was part of the touring production of Les Misérables as Monsieur Thénardier.
Kostroff is an active member of the Musical Theatre Guild-based theatre company-seen musicals. This theatre company performs rarely. The Musical Theatre Guild is a Los Angeles. He was part of the touring production of Les Misérables as Monsieur Thénardier.