Strathairn is also a stage actor and has performed over thirty theatrical roles. He performed several roles in stage plays by Harold Pinter. He played Stanley in two consecutive New York Classic Stage Company (CSC) productions of Pinter's 1957 play "The Birthday Party", directed by Carey Perloff (since 1992 artistic director of the American Conservatory Theater), in 1988 and 1989; the dual roles of prison Officer and Prisoner in Pinter's 1989 play "Mountain Language" (in a double bill with the second CSC Rep production of "The Birthday Party"); Edwin Booth in a workshop production by W. Stuart McDowell at The Players in 1989; Kerner, in Tom Stoppard's "Hapgood" (1994); and Devlin, opposite Lindsay Duncan's Rebecca, in Pinter's 1996 two-hander "Ashes to Ashes" in the 1999 New York premiere by the Roundabout Theatre Company.