Ginsberg has been active in the theater community since performing in both "The American Clock" and "The Resistible Rise of Arturo Ui". He spent three seasons at the Williamstown Theatre Festival where he met friend and mentor Olympia Dukakis. The two have worked together on a number of plays over the last twenty years including "Mother Courage" and "The Cherry Orchard". In 2015, an "excellent Maury Ginsburg" appeared in the Off Broadway Cherry Lane Theater's "Laugh it Up, Stare it Down", playing a series of different characters that impact the protagonists' lives. In 2016, he appeared in the Pulitzer Prize winning play, "Disgraced", at The Cincinnati Playhouse. The Cincinnati Gazette described his work as "distinctive and outstanding", "The Cincinnati Enquirer" referred to it as "superb". In 2019, on the heels of the Tree of Life synagogue incident in Pittsburgh, Ginsberg performed in Paula Vogel’s "Indecent" at the Pittsburgh Public Theater. The Pittsburgh Current described his performance as “the foundational center of this production playing Lemml with a power as quiet as it is electrifying.”