Marshall made his Broadway debut in 1944 in "Carmen Jones". In 1950, he understudied Boris Karloff as Captain Hook in the Broadway production of "Peter Pan." He played the leading role of De Lawd in the 1951 revival of "The Green Pastures," a role he repeated in 1958 in a BBC telecast of the play. He performed in several Shakespearean plays on the stage in the U. S. and Europe, including the title role in at least six productions of "Othello". Harold Hobson of the London "Sunday Times" praised Marshall’s portrayal as "the best Othello of our time."